Explaining SSDs: The Price/Performance Trade-off
Вставка
- Опубліковано 31 тра 2024
- SSD update video focusing on SSD technologies, life expectancy, SLC cache, and DRAM vs DRAM-less SSDs. Or in other words, this video is about why some SSDs cost more than others, and the performance implications of getting a lower-cost drive.
For information on SSD form-factors and interfaces, please see my previous video: • Explaining SSDs: Form ...
And my Cyber Security: Backups & Encryption video is here:
• Cyber Security: Backup...
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Chapters:
00:00 Introduction
01:02 SSD Technologies
08:14 SLC Cache
11:48 DRAM-Less SSDs
13:39 Wrap
#SSD #DRAM-less #SLC #Cache #ExplainingComputers - Наука та технологія
This man is truly one of the GOAT tech UA-camrs
Thanks for never disappointing, Chris!
Thanks.
This man is a treasure. But so disappointing to hear about what manufacturers are dumping on us. Scary.
@@ExplainingComputersso Chris, I assume one should use HDD as NAS or backup devices instead of SSD'S?
@@ExplainingComputersby the way great information video. Didn't know all the difference in SSD'S
Agreed He definitely has some of the best UA-cam tech videos that are not only informative and entertaining but you don't get a whole lot of bias it's just straight his opinions based on his findings nothing more nothing less than I can always appreciate that in a UA-cam channel
Thank you for reading this and thank you for your content sir I hope you're having a good day
God bless you and your family
God bless you
Jeremy Scruggs
This should be held up as the "Gold Standard" by which all technical explainer videos should be judged. Clear, concise, broad yet detailed coverage of the topic, and lots of "why" mixed in. I tip my hat, sir.
These are the aspect of computing that Linus Tech Tips cannot explain. Or if they can, they just gloss over gleefully for the sake of click bait without going in-depth.
Good thing we have ExplainingComputers to explain things thoroughly.
Thanks, appreciated. :)
@@ExplainingComputers I await your "water cooling Mr.Scissors using a swimming pool" video with much anticipation, Chris.
Just kidding. I do enjoy LTT. But, like, you go to them for computer-based silly entertainment, you come here to actually learn something.
@@klaxoncow But its not that deep enough, to reveal some non-obvious details: for example Anandtech benchmarks many HMB SSDs. But there is no hint how to query the state of the HMB buffer state (enabled or disabled?). As you can even disable HMB comoletely, then the performance drops down to prev. gen. DRAMless level. How much RAM has been allocated to the HMB buffer? As it can also vary!
That's true and they where (Linus tech tips) suggesting major SSD manufacturers where involved in "bait and switch" tactics but I don't believe industry to be anywhere near that cynical...if drive speeds fall short of claims then i'm sure there's some other reasoning for that perhaps its industries hierarchical order the available quality of materials or supply chain issues but not outright swindlers as Linus has once boldly claimed..
@@ricsip
I've looked it up for the Crucial P3 1TB, a cheap PCIe Gen 3 SSD. It apparently uses 64MB of system RAM as HMB. Even if another model used let's say 4x the amount that's not a lot on a rig with 16GB plus.
This is what I love about this channel, you learn something new every episode.
Even if you think you know all there is to know, along comes Chris and says 'Hold my beer...'
Top stuff, top creator. Have restful Sunday Chris!
Thanks my friend. :)
Exactly. I thought I knew it all. But no🙂
@@tvsmed Nobody knows it all. Stay humble.
Oh hello Mr. Muggie! And how is my favorite FreeBSD UA-camr?
@@esra_erimez You know how to say all the right things....🙂
Things are fine, and yourself this fine sunny October day? (here in the UK at least......)
I retired from a nearly 40-year career as a computer and network admin. This has always kept me close to the hardware and how the operating system uses it, especially in the earlier days through the evolution from mainframes and minicomputers to common standards-based ISA and PCI systems with mass produced expansion cards. This particular tutorial is excellent, and has expanded this old dog’s understanding of non-rotating storage devices. I was vaguely aware of the cycle-based limits on lifespan, and now I see the details far more clearly. Thank you..
Probably the missing part is to talk about how HDD also has a controller (many people don't realize how everything abstracted) and that both SSD and USB-flash drive sticks are both flash-based and basically the same thing. The differences are in the number of chips, etc. and how fast & smart the controllers are.
isa.. lol bin awhile since I heard that. still going though.. started with a 8088 too.. in fact I still got 4 working ones :-\ what's with old techs keeping old as stuff... whats this... a voodoo 3dfx ..... oh come on LOL
This should be required viewing for EVERYONE who owns a PC. Mr. Barnatt makes it so simple to understand these concepts!! So many of my computer customers have no clue, and never worry about maintenance of their machine.. all they do is cry when things break and they don't backup. I do my very best to have my best customers watch as many of your instructional videos!! You do more for responsible computing than any youtuber that I have ever seen!! Keep up the great work, and we need to call you DR. BARNATT!!!
Many thanks for your kind feedback. :)
A Christopher Barnatt 301, 401 and 501 course at college/university level, with lectures, workshops and internships... You should make sure you have adequate security when you register! Crowds and waiting lists... !
Professor Barnatt in my book top video as always Chris
I once bought a dram-less Sata SSD. Never again. Saving a few coins isn't worth it. Better to buy one with dram.
Aye, but it's not something generally listed in specs
In general I agree with you. Some ssd controller chips actually have a fair bit of dram built in. I'm not quite sure if they count as dram less because I think all controllers have at least some dram built in. The wd blue blue in particular seems to never get bogged down the way some other discount drives do - tho its maximum bandwidth is pretty limited , it does at least perform consistently
Yes, they're horrible. Worst is that manufacturers can still report really good speeds, but not revealing what amount of data it was done. Also this definitely should be mentioned in datasheets. WD I bought didn't have this on data sheet 🤬
They're OK in some cases. The DRAMless Silicon Power mSATA drives are often cheaper than a flash drive in the same size. I would also stick one in an old computer. I don't ever use them as my main drive in my laptop or desktop.
@@kattz753 Well I gave review for vendor that it's ok for NAS usage to ie. view/listen media over network or possibly as gamers data storage drive. But absolute garbage for usage were there's a lot of writes happening.
This is award winning level education! Thank you Chris for a thorough yet understandable overview of SSD technology.
You are an educator extraordinaire!
Cheers from Canada!
Wow, thanks!
I couldn't agree more! (From Montréal!)
We've come full circle. I subscribed when you last talked about SSD and now, how the landscape has changed.
Ah yes, things keep coming around! :)
Sunday Morning Solid EC
God damn, it's like the fog has cleared. I am now a more savvy consumer. Brilliant!
There is one HUGE negative to D-RAM less drives that Chris didn't mention. They CANNOT be used in external drive enclosures/external drives because they require your pcs RAM to function. I found this out the hard way recently, and it took hours of hair pulling and frustration to figure out WTH was happening. Don't buy D-RAM less drives! The minor savings are not worth it.
Now this is a great point -- which I guess only applies to the new generation of DRAM-less drives (as those that store their map in their NAND flash should work in an enclosure).
it's a bit extreme to say that you shouldn't by drives without a dram cache just because you can't use them in external enclosures. the savings can be very much worth it, it's just something to be aware of, just like the potential speed difference.
@shade221 obviously people can do whatever they want, it's their money, but I won't rich them with a 10 foot pole.
@@kurtisrinker1202 very few people at the moment are going to use an SSD in an external enclosure. the potential speed difference is a way bigger factor for most people.
Really? Is this new? I have never seen a working drive I couldn't access through my SATA to USB or M.2 NVMe to USB adapters.
... any specific models?
OS running on SSDs has been so much better than disk drives...faster, more reliable, never corrupted or crashed. Disk drives were a constant problem.
Been watching this channel for 5 years and one thing i can say I love about this channel is the very retro, feels like 1987, computer theme song that happens in the opening.
Oh look 👀 Chris is in a solid state of excitement driving home his ssd’s!
Cadence. That's just 1 thing about what I love about this channel.
I think it's getting close to 10 years since i first started watching your videos Chris. Thankyou so much.
Your ssd explanations are the best on the net.
Wow, thanks!
Recently found this channel and he deserves a lot of praise.
I came here wanting to learn about DRAM-less, and he definitely covered it.
Plus, I learned a couple other things I didn't know about SSDs.
The added graphics are really nice.
10/10 channel. Easy upvote from me.
Thanks. :)
Excellently explained once again. In just under 15 minutes I'm thoroughly and masterfully informed. Life expectancy of SSDs is what really does worry me the most actually. I just don't know what exactly is to expect in terms of practical anticipation defined in years of use. I can see SSDs for starting up the OS but best leaving working data, files and backups on a physical quality platter such as WD, so it seems.
You can check how many terabytes you have written via software.
In my case, I'd have to use my PC for at least the next 30 years every day to hit the TBW, and realistically much longer than that.
Very good, Sir! Now pop down to the local establishment for a well-deserved drink!
I think most manufacturers hide most of the info on their SSDs and will only tell you the max read and write speeds and IOPS, and no information about dram or cache or anything 😓
This is by far the best explanation of SSDs I’ve seen. So thank you for that. As a next step, can someone pls create an online spreadsheet for SSDs with columns like Type of NAND (SLC, TLC, QLC) | SLC Cache | Interface | Max expected speed | Measured Max Speed | DRAM-less |. It’ll make buying process so much easier
That would be a very useful table! :)
I can’t believe this video is free. I learned so much, thank you.
Another excellent video, with lots of great information!
Here's hoping that SSD size and price will soon be able to compete with HDDs for NAS use. :)
I wish but doubtful, HDDs are still KING for storage.
Seagate just released 24TB drives and roadmap is 40TB drives in 2 yrs
@@Argedis But, they're Seagate...
@@FlyboyHelosimSeagate's high end drives are fine. If you don't like Seagate you can always try Toshiba.
24 TB for SSD is easy to achieve but price .... 2.5 case you can easily make ssd of size 100 TB @@Argedis
@@FlyboyHelosim but HOPEFULLY they are!
In Seagate, in last years, they have demonstrated that seriousness is something that worth it to be put within products and market(ing).
Western Digital continues to make errors without exiting the mud pool in which they put themselves into, with a lot of scandals.
Personally, I had always been using WD, but when I arrived to the point that the second, then the third, and then the fourth WD RED HDDs went to be get rid off because they were completely unusable after 1-2 years, and subsequently the CMR/SMR scandal went clear, can you imagine my feelings about WD...
I still use with proficiency and satisfaction my Seagate's HDDs, with some of them being also (very) old but stil performing very well and SMART values still in good shape.
I must 'disclaim' about two things:
I am still talking about 3.5" and rotational HDD; and no SSDs of mine are from either WD or Seagate. I use the most Crucial, Samsung and Kingston. Sometimes cheap Silicon Power's one, which I find are a bargain in price/quality ratio.
Please be gentle with my not first-language explanations...
For someone strongly thinking of getting an SSD for an old HP15, Mac Mini 2012 and my PS5? That was super helpful, truly. Thank you.
this is an excellent video dropping legit knowledge on what we use everyday.
it’s a refreshing step away from a lot of other youtube pop “tech” channels unboxing buy-this buy-that consumerism videos, which has a time and place… where anyone can open a box but not much knowledge is gained.
A very thorough and clear explanation. Some time ago when I read EVO 860's slow down when copying a file larger than ~60 GB (I think it was that value) I changed to the Crucial MX500 as that one has a dynamic SLC cache and doesn't appear to slow down.
Those MX 500 drives are actually very consistent if you can afford to stay below 1/3 capacity. Still cheaper than enterprise drives but with the low utilization they're only writing to the SLC pages and never need to garbage collect
@@shanent5793 yes I like them very much
The question is, who except for professional video editors is gonna do that regularly? If you download a game for Steam the drive transfer speed won't be the bottleneck, and even if you record let's say a 30 min gaming session in FHD as a background for some kind of talking video putting a new audio track on a 20GB file won't overwhelm even cheaper PCIe drives.
Clear and concise explanations are why I started watching EC!
This is great. Before this video I knew 1) what SSD stands for 2) they wear out 3) they are generally faster than HDDs. Everything else was learning for me. I use an SSD as my system drive but I do store other stuff on there as well so I'll be taking a look at how much it changes and consider wear.
Now the Samsung 990 PRO 4 TB has been dropped to $299! I bought 4 and made a 16 TB RAID level 0 using the OWC 4M2 Express enclosure . It is a joy! Thanks for this superb article.
I only recently took the plunge and added SSDs to a couple of my computers. They're quicker now. Not crazy fast but definitely snappier.
Chris, I upgraded my SSD to my newly built computer. WD Black NVMe Game Drive 2TB GEN 4 from a Samsung 970 EVO PLUS NVMe 500GB.
Corsair 110R Case, Intel Core 12th Gen Inte Core i5-12400, 2500 MHz 6 Core 12 Logical Processor
Gigabyte H610M S2H DDR4 H610/Intel LGA 1700/Micro ATX/DDR4/Single M.2/PCie 4.0/USB 3.2
Corsair Vengeance LPX 32GB (2x16GB) DDR4 DRAM 3600MHz Desktop Memory Kit.
Gen1/Realtek GbE LAN/Motherboard) EVGA 750 GD, 80+ Power supply Thanks for the great content and information on SSDs.
Sounds good. That's a lot of extra SSD capacity. :)
Thanks for explaining that so clearly Chris. It's very helpful to understand the reasons why certain cheaper ssds might not be as good of a deal as they appear, although for general use they are okay. I have a good quality system nvme drive and a decent larger drive for game storage. I do a little bit of video editing but nothing that requires massive reads/writes. I might see if any good deals pop up before Christmas as drives like the Kingston Fury and Western Digital 850X have been a nice price in recent months. As Samsung recently brought out their 990 Pro drive the 980 Pro has also seen discounts. These cost so much until fairly recently so it's nice to see prices come down. Long may it last! 😁
Very good video(short, clear and pretty much all encompassing) except Chris didnt mentioned one aspect of the SDD'd - data retention.
All SSD's can retain the data a certain amount of time while not powered, usually around a year, after that it starts to lose the data stored in it. This argument ties well into "No SSD is a permanent data storage" statement at the end of the video.
Fair point, except that two years is generally taken as the norm before data needs a refresh (via a data read, not re-write). But the more P/E cycles a drive has endured, the less time data will remain.
It would be very interesting to see the computer setup you use as your daily driver, a tour.
I don't know, Chris... SSD's are bulky in size. A 5¼-inch floppy is much more sleek.
:)
Of course in some laptops like Apple Macbooks, the NAND flash chips are directly soldered to the logic board which means you don't any choice as to upgradeability.
Sadly so.
This is what stops me ever buying another Apple product. They are built to fail.
So you don't want to use (external) HMB SSDs, as they further increase the wear on your Mac's SSD
@@cromulenceyou shouldn't have said that 😂😂😂
@@Super8Rescue They're so concerned about the environment, though... /s
Another masterclass from our leading teacher... I've finally understood how the SSD in my DELL laptop behaves during file transfers (the size of the cache memory...). I'm sure many of Christopher's other admirers have gained new knowledge thanks to this update. Definitely material for computer science students! Thank you for this!
Thank you Chris!
You explain things so well to the layperson - it’s a talent, I appreciate you.
Thanks for making sure TBW was in there. It's good to note that TBW is often used to limit warranty (like "1200TBW or 3-years, whichever comes first") but that DOESN'T mean a drive dies when it exceeds rated TBW. It does mean it's less reliable at storing data long-term + power-off. But I have SSDs at 3x their TBW still working with no errors.
Chris you are a real treasure. 👏👏👏
Not that this technology existed back then, but I had a flashback to watching Open University as a kid while watching this and I absolutely loved it. Awesome as usual!
Enjoyed the video. One thing you didn’t talk about with the newer drives is heat. PCIe4 &5 drives generate a lot of it. I tried to use a 4TB WD SN850X in an Orico 10Gbps external enclosure as a backup drive. Over a period of about 30 minutes it overheated and did not throttle, rather it just crashed and needed to be reformatted (MacOS). So best to avoid external enclosures and use these with a heatsink and active airflow.
It doesn’t matter anyways. The SN850X would obviously not be able to take advantage of the full speed with thunderbolt 3/4, much less 10gbps usb 3.1.
Interesting. I have experienced similar problems with a SN850X 1TB in three separate external enclosures with my M1 Air and M2 Mini. Oddly enough it seemed to work fine in external exclosures with my Windows machine (in eXFAT). On the Macs, in the midst of large-ish file transfers it would start rapidly disconnecting/reconnecting frequently and I generally had to reformat.
wow already sunday"s afternone !! have a good week next all viewers !!!!
Time flies!
Wow, I never watch any video about SSD that are digestible by my BRAIN. Love your work.
Thanks. :)
This was a very useful video Chris. I bought a DRAMless M.2 SSD a couple of years ago to be the system drive in an HP desktop. I knew there were tradeoffs but you explained them well in this video.
Thanks for more very useful info Chris. It seems that as a rule of thumb in consumer SSDs the TBW figure is roughly half the numerical size of the drive and given should give many years of normal use before failure. Most SSDs also have 3 to 5 year warranties. But as a professional I have seen SSDs fail without warning long before reaching anywhere near their advertised TBW or warranty period. And once they do (unlike with magnetic drives) you can more or less forget about recovering any data from them. Admittedly in the same breath I had a WD 4Tb magnetic drive catastrophically fail two days after buying and partitioning it, and it was completely unrecoverable. So I guess having a good backup strategy is increasingly important these days.
Man the level of explanation, salute.
Love the way you speak and show the examples of the workings.
And here we meet again on exciting Sunday 🌞🖥️
Greetings!
Greetings!
No bullshit channel, I love that. Just 1.25x to get rid of awkward silences at the end of the sentences.
Thank you, that was interesting. specifically, the fact that leaving an ssd less than 90% full so it can shuffle data around easier. I already did that because hard disks liked that to prevent fragmentation so it's nice to know that this still holds true but to prevent wear instead.
I know that many defrag utilities stated not to be used on SSD's ... NOW I understand why!
@@lesliedeana5142 The reason why defrag programs aren't used on SSDs is because it doesn't make sense. SSDs don't have tracks, sectors and clusters, neither they have moving arms and heads. So they don't need to reposition the head to another track or sector if a (large) file spans over more than one of them, like mechanical disks do. SSDs are electronic devices, capable of accessing any block of storage immediately, without any repositioning or rotation latency involved.
Excellent job gathering volumes of technical data and presenting it in a short, concise video that the layman can understand!
I love that you've kept your early 1990s technology style theme. You're brilliant!
I really needed this video, great timing! TX
I'm going to watch this in full when I get home later.. I'm certain that it will clarify the world of SSDs for me...
Good morning from the states I have to say this is one of your best videos in terms of knowledge really liked it...
A very succinct, easy to understand explanation.
Fantasticly informational video! Thank you.
Well done presentation Chris!
And here I thought there was something wrong with the speeds on my new Samsung 970 EVO PLUS SSD as its functioning perfectly normal as demonstrated in this highly informative video. Thanks for the valuable tech lesson Chris! 👍
You've covered everything one would need to know when in the market for an ssd upgrade or expansion (being already familiar with basics like form factors, etc). Briliantly clear, concise, and devoid of the typical YT faff. Many thanks for your efforts here!
Have an slc drive in a openbsd firewall and it's been running for over 6 years without issues. But it's not being written to alot. Great explanation!
Still using the same boot drive 240GB Kingston SSD from 2015 that was slated in reviews on release. Doesn't seem to be any reduction in capacity. A many-times upgraded and updated Windows still up and fully running in
Kingston SSDs have in my view often had a lot of unreasonably poor press.
Hey Chris. Another great educational video. Even though I have been in the various tech industries for a long time, I still learn something new each time you present what are very relevant subjects.. This tutorial on SSD's is especially relevant, as they seem to change every time I purchase one. I too have always used the old one-two approach to computer storage: SSD's for the operating system, HDD's for data storage. It has always worked well. Thanks for making it clear what to look for when purchasing a new SSD. At least for now! Thanks for all your hard work!
Wonderful. I've kind of picked up a lot of that by reading around over the years, but it is so good to have it all laid out clearly, with good guidance on what matters for which uses. Mostly, for my low intensity uses, it evidently doesn't matter much at all, except that this is one area where bigger really is better.
Thank you so much for this video! It answers many questions for me that will prove useful in maintaining the equipment at work!
Very interesting video and this will be a great help in buying a new ssd, thank you for all the time you put in to your channel.
Outstanding video. Very clear as always. Thanks, I never understood the inner workings and why some SSD's seem faster for large writes than others.
Thanks again Chris, for all this info. It makes your head spin, trying to think of all the aspects, while choosing your next SSD.
The best explanation of every concept. What an excellent video, especially on the meaning of bit level acronyms. I've been buying Samsung Pro SSD's exclusively for many years. I did not know they were retiring TLC. I guess I'll have to keep buying older drives.
I have TLC SSD's that are 15 years old at this point and used almost daily. All still functional.
Thank you for all the hard work you've put in bringing us interesting weekly content. Today I've certainly learnt more about SSD's which I still find quite a fascinating subject, a happy Sunday to you & the crew :)
Thanks Alan. :)
I've learned modern SSD's HAVE to do internal wear leveling in order to maintain performance.
I have a 2TB Samsung EVO that started freezing when doing write operations and even benchmarks showed as low as 100MB sec writes.
The drive barely had 5 TBW and only 1/2 capacity was in use.
I ran manual windows TRIM operations and nothing helped. After doing lots of research I've learned SSDs do their own internal 'cleanup'. Moving data around and clearing cells to optimize write performance on new operations. It took several weeks and now write speeds are back to normal.
Apparently this is all done through the SSD controller and is a 'black box' that we have no control over.
This happened after doing a couple hundred GB of write operations. Read speeds were unaffected.
Yes, as discussed in the video, an SSD's controller constantly performs wear levelling over which the user has no control.
when I saw the title, I thought: yes, I know SSDs.
after I saw the video, I now think: okay, I know a lot more about SSDs.
which is actually quite nice 🙂
There is so much more to this than I realised. A great explanation. Thank you.
That was the best lowdown on ssd's i've ever seen or read. Detailed and easy to understand. 👍
Excellent video finally I can make sense of all the ssds on sale. Thank you for sharing your knowledge
Very well done and easy to understand overview of the technologies!
Super interesting as always Chris. Big thanks for educating us.
Excellent presentation Chris, thanks for sharing your amazing knowledge in a great format (no pun intended).
Thank you, Explaining Computers 👍
Yet again a richly-made and historically significant video.
Kindest regards, neighbours and friends.
Thank you very much for the information and great presentation sir🙏
Nicely done. With manufacturers (ahem Samsung) throwing around acronym's like they were candy, you've cut through the technobabble hype and made choosing an appropriate drive easier (even for the lay person). This video should be made mandatory for anyone looking to purchase a SSD drive. i realize this was specifically about SSD drives, a few wise words on the interface's would be helpful, especially on the M.2 format. Perhaps something for the future.
Thanks for this. I cover interfaces in this video: ua-cam.com/video/EXLfErPEYiw/v-deo.html :)
@@ExplainingComputers Awesome! And my apologies, I'm still new to your channel. I/m going to allocate some free time and go over the back catalogue.
Awesome as always Chris - I have always appreciated how you are able to explain very technical concepts in an easily understandable way!
My old NVMe i still use, 2 Tb 9800 by Samsung, cheaper, i can see that !
why all channels say cheap now ? Need it, how many NVMe slots on i7 ?, need i9 cheap now ?
Thanks for this and all other videos! I always enjoy watching them and learn a lot!
Thanks for your very generous support. :)
I always learn much more than what I come for. What a channel!
Every time a fantastic review of what also we IT technicians must expect from the market...
Thanks Christopher, you are the lighthouse in our difficult sailings...
My first hard disk was an Apple HD20. 20 Megabytes. Cost about $1200, or more than a 1000 times as much per byte compared to today. Transfer rate of about 60KB/second. And we were perfectly happy.
Great point. :)
Sunday greetings! Thank you for explaining computer's SSDs. I will need to watch this one a few times to get it right/write :) Hidden manufacturers specs drive me batty. Stay well!
Thank you for explaining this topic!!
Brilliant video, thank you very much for educating us
A very solid video on solid-state drives! Terrific as always. :)
OMG! Why can't SSD manufacturers at least agree upon terminology?
How's a consumer supposed to keep up?
A: Watch ExplainingComputers.
Thank you Chis, because we don't know what we don't know!
Thanks for this magistral masterclass on SSD Storage !
Very very interesting. Thank you so much for your beautiful explanation. Have a nice week.
Thank you so much Chris! Very useful video.
Great overview. I would add a few things. I prefer to decipher TBW as "Total Bytes Written" rather than Tera Bytes Written for the simple reason that with older drives, manufacturers specified in GB, and now with the big capacity ones we get into PB territory.
In the old magnetic platter days, we called the sustained write speed that a drive fell back to once the fast cache is saturated "media speed" and the same concept applies to SSD now, as you explain. A S-ATA III drive with a 6 Gbps (750 MB/s) interface may have a media speed of only 50 MB/s. Especially in the flash memory for high resolution * high speed cameras we see a need for very high media speeds or sustained write speeds.
The write speeds on flash memory cards, generally, is burst speed and only valid as long as the cache is not saturated.
We also see cards that have higher sustained speeds with increasing capacity and this is not the consequence of more cache - because sustained - but likely something like RAID 0 or dual I/O controller chips inside the card.
Over-provisioning - Having worked in enterprise IT, I can add that a way to raise the number of P/E cycles in flash memory devices is to just put more memory in than the user and operating system (host computer) will see. So the usable capacity is what is on the label, but under the hood, for wear levelling, there is, say, 50% more. In the round-robin storage of data in fresh blocks (even after wiping a file from the FAT) the added capacity then results in more P/E cycles or higher TBW.
Reduced overprovisioning - we also see capacity numbers now that are outside the standard 2^n (n an integer) numbers. Imagine an SSD that has cheap memory cells but for TBW got 50% more - say it's 512GB on the label but has 256GB overprovisioning - and this SSD is sold for 1.00X. What has happened in recent years is that manufacturers had less complaints about SSD failing too early from consumers, so they shift part of the over-provisioning to usable and label. The 512GB now becomes 640GB with 128GB under the hood and the price now becomes 1.25X - for the same material.
The most important most overlooked property of SSD and flash memory is how long data retains integrity when the SSD/card is taken off power. Some cards have data integrity protection and maybe some SSD too. Ask a collective of people with a Ph.D. in electrical engineering and quantum physics for a number and you may get 7 to 7,000 hours as an hour.
In the light of wear levelling and consumers buying SSD that have low P/E cycles, today's advice to never switch a computer off really makes sense.
If you need reliable storage with a high number of P/E cycles (TBW) today, then rather like buying SSD variants, I would buy CFexpress Type B cards from a brand with a very good reputation (such as Delkin Black and Power series). Put these in a Thunderbolt reader/writer and its fast, very fast too.
You can decipher TBW as what you wish. But if you read a modern SSD specification, the term is most certainly used to mean terabytes written. Manufactuers do not write "Endurance: TWB: 500TB" they write "Endurance 500TBW". Language evolves.
@ExplainingComputers love your end of a video
:)
Hi Chris. Thanks for the update. Quite refreshing indeed.