486SXLC2-40 Cache On vs Off Comparison
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- Опубліковано 2 лис 2024
- This is the part of the previous video that was blank. It's an excellent showcase of what *8KB of L1 cache can do vs having it disabled. This also works excellently for slowing down a system so that you can run timing-critical games like Wing Commander while being able to speed the system up for Doom or Heretic. Hmm, I wonder if the turbo button on these disables the cache...
Sorry for the auto focus going nuts.
I said 1KB in this video segment, it's actually 8KB.
Thanks for the update. The performance increase is also related to the fact that the clock doubling is only relevant when a L1 is present. If it is not, the CPU has no other choice than waiting for the memory, and it spends litteraly no time at 40 MHz (thus behaves like like a 20MHz 386SX).
It'll be a slight bit faster than an SX-20. It's not a big improvement but the times that the processor is actually working on something it'll behave like an SX-40. Not that it is a huge part of operation when it has to externally fetch literally everything it has to do but yeah.
Cool content! I've been working on the same stuff and have a few of these CPUs. Especially those 286 to 486 upgrades I find fascinating. Currently working on maximizing the performance of a stock 5170 mainboard. It has 8 megs of RAM and this very same 40MHz 486SXLC2 CPU on a little interposer. It's an ultra rare Evergreen 286 to 486 board 🙂
This must be the PCChips board. I've got the same one but it's an older version and it does 30MHz max. with the SXLC2 A bit of a bummer.
I just finished repairing an ALi board like yours and that's an excellent board! The PCChips/SARC board? Not so much..
I wondered: In your previous video with the 50MHz overclock on the ALi. Did you find out what CPU that is? Maybe I can run my SXLC2-40 at 50MHz as well but I first have to do some desoldering. I also have a Ti486SXLC2-50 on the way but that's a (-GO) 3.3V part so I'll have to build a little VREG circuit for that if I want to use it.
It may also end up in my PS/2 Model 30 which has a 33MHz 386SX in it now but I'm a little affraid to mess up that wonderful Kingston upgrade board.. ;-)
The SLC is just a standard SLC from what I can tell. The chips on the donor board it came off of looked to be a late model so it was likely similar to the 486SXLC2s we can still order on eBay and they are/were meant for repairing embedded systems. At that point they were so good at making those processors they end up almost all being 'unicorn' units.
As for being able to tell if it was actually a 50MHz that was rebranded, I have no way to tell. It might have been but the top of the processor wasn't engraved or anything, it just had a sticker on it.
Making the VCC 5V for that chip shouldn't be too bad. A lot of these boards are dual layer so they end up with only 1 or 2 power traces going towards the actual processor instead of a huge plane. Intercept those and regulate down and you should be good to go!
Hope your swap goes well! I'm about 90% sure that SXLC2 is going to end up on the 386SX ALI board and the 386SX is going to get moved to the PCChips board. It only makes sense at this point.
@@DKJones96Yeah it can definitely be done. I saw a forum post on a Spanish website where a guy upgraded stock IBM PS/1 2121 board to a TI 486SXLC2-66! I mean that's an insane upgrade. He just swapped the 33MHz crystal with a 66MHz one, cut the VCC lines (except VCC5), made a little breadboard with a 3.3 VREG circuit, plopped on the clock doubling 66MHz CPU and it just worked! He managed to get around a 700% performance increase and Landmark (not the most reliable, I know) even gave a 1200% increase compared to the stock 16MHz SX! Now that's one inspiring boost! Love that stuff, just like your content and that of Atheatos! Taking hardware to the next level using period correct parts on stock mainboards.
The era this hardware was produced is one of the most interesting because those cheaply built one chip mainboards that were essentially highly integrated 5170 clones with a 386SX-class CPU instead of a 286. Because of that there is no platform to my knowledge that has more potential for upgrades because of awesome newer technical developments like L1 cache, clock doubling and the 486 instruction set. With my Super 5170 build I managed to leap from 1984 to 1995 (the upgrade CPU is from 1995). The AT was definitely ahead of its time!
I saw a guy on a forum somewhere (can't remember) who got rid of the slow DRAM (this and the 6/8 MHz bus was essentially what was holding these machines back) on his 5170 and swapped it with SRAM entirely, removing all wait states and refresh cycles. That thing was also very fast!
IBM did a lot of cool things with this tech as well in their entry level systems, using their Intel 386SX license. They managed to squeeze everything out of that deal. Their SLC ("Super Little Chip") is FAST! No one could beat those things, esp. the 100MHz version. A 100MHz 16-bit CPU, that's insane!
I hope to get my hands on one one day. Too bad that will require buying a complete mainboard or an upgrade board as they weren't allowed to sell them separately and are pretty hard to come by..
Ah yes, the missing part
No idea how it ended up being blank in the original post.
That did not show any results to compare...