Hacking a 486SXLC2 (8KB of L1 Cache) into a lucky 386SX Motherboard. Insane performance boost!

Рет қаралды 4,433

Күн бұрын

OK, I promised... I am delivering!
I modded my 386SX Lab Rat with a 486SXLC2 CPU.
It is advised to first check my Video review of this M/B:
• 386SX Motherboard Revi...
The 486SXLC2 is the top 16bit bus, Cyrix based, 386 replacement CPU!
It features 8KB of integrated L1 Cache and a clock doubler.
- The mod was a success! The results were mixed.
- I do not wand to spoil this too much in the description.
- Lots of tweaks, benchmarks and interesting conclusions in this Video.
- I also broke my 386SX Overclocking record (more maybe possible).
* There is something important I missed (said wrong) in this video.
* The OP1 is NOT the Flush signal, it is the A20 than connects to the keyboard controller.
* Flush is not connected on the CPU here. I mixed these two a they are next to each other.
* A20 is needed for the correct operation of the L1 cache (with the 64k boundary option enabled).
* This explains the behavior when I played with the different flags in the cyrix utility.
* I will come with an update video on this topic (along with some other stuff).
Now, I am not going to put these CPU modules into the store.
But if someone is really interested we can discus this.
Benchmark results:
docs.google.com/spreadsheets/...
K2s Retro Workshop - Cx486SLC 50Mhz Video:
• Overclocking the 486SL...
Vogons "Register settings for various CPUs":
www.vogons.org/viewtopic.php?...
-- TIMESTAMPS --
00:00 - Intro
02:09 - Cyrix 386 Replacement CPUs.
04:30 - About the 386SX and 486SXLC Pinouts.
07:22 - The Flush signal on the Motherboard.
08:38 - And the mods are in!
11:25 - Results with the 386SX.
13:42 - Results with the 486SXLC2.
24:39 - All Benchmark Results.
29:29 - Outro
This one had a lot of work. I hope you will enjoy it!
Please like, comment, share and subscribe for more!
Support me with PayPal so I can bring you more Videos like that:
paypal.me/galanopu

Пікірлер: 73

@pipschannel1222 8 ай бұрын

Super interesting content! I've been working a lot on " SUPER SX"-builds like these, just like you and K2. I have both the ALi and a variation of your board (an M396F with the SARC chipset) and the ALi is more suitable for upgrades like these SXLC2's, just like K2 experienced. The M396F is really primitive and lacks a few connections. On my M396F clock doubling doesn't work either but I have an earlier version that doesn't even have that little "op1-bridge/jumper". The maximum I could get out of that board is 30MHz without clock doubling. I think the ALi board K2 uses (same one I just bought for a very small amount but with tons of battery damage ;-) ) is a lot nicer to run CPUs like these as they have more connections to the chipset for cache coherency. I still have to figure this for myself as I just got the ALi board but out but I think with the little adapter you made these things can easily run at 50MHz without clock doubling, just like K2 did, which of course makes for a nice build. If I could only get one of those little adapter boards like you made... I will contact you about this separately! The IBM chips though really are the unbeatable SX class CPUs: Clock for clock they are a lot faster and they can also be clocked faster but are near unabtainium, especially on their own as IBM didn't sell them separately. To give you an idea of the speed of those things: My 16-bit IBM 486SLC2-40 upgrade easily outruns an SLX2-40, which is the 32-bit variant of the SXLC2.. Pretty impressive little CPUs those IBM SLCs! Especially my IBM SLC3 is really fast for a 16-bit CPU. Runs DooM like nobody's business! ;-)

@atheatos 7 ай бұрын

I have so many new motherboards myself now too. Just absolutely no time for anything right now :/ On top of this, I have accumulated so much hardware I do not know what I have and where. I am trying to organize now. I have a few of IBM SLCs. These are for sure totally deferent. Based on original 486 core by intel. The biggest problem for me is the lack of documentation / pinout info. I will come back to videos at some point, I have so much to do and show to the people. :/

@pipschannel1222 6 ай бұрын

@@atheatos Very nice work you did here indeed with those little interposer boards 👌 Yeah, there's plenty of documentation on TI/Cyrix chips but IBM has always been very secretive about their designs and didn't share a lot because they didn't need to. You know: Those TI chips were meant for clone PC builds so they had a lot of incentive to share the way to implement them because it was directly linked to their sales. IBM was on the other side of the spectrum though. They were sick of the vast amount of clones eating up their market share and they very much wanted to dominate the PC industry again like they did with the 5150, 5160 and 5170 (their very succesful 1st gen/old school PCs) so they locked down every bit of low level technical detail and wanted to produce their own CPUs.. Even their technical reference manuals were very limited in terms of design decisions.. They really didn't want anyone to steal their designs again and hence they were very protective, which is of course understandible but which is also why I have great respect for other companies like Compaq who blew the clone market wide open with their crusade for open system standards 👍👍 It's the guys from Compaq who initiated IBM's demise in the desktop PC market but that was inevitable in the end as they opened the doors ten years before by designing their first PC by using of the shelf parts.. The irony 😄

@Stoned_Raiders 6 ай бұрын

Just watched your video on modding the 386SX to 486, and I'm seriously blown away by the quality of your content and explanations! Your work is fantastic, and I'm itching to try it on my own 386SX 40 MHz. Thanks a ton for the top-notch content and insights. Truly impressive!

@atheatos 6 ай бұрын

Thank you for the comment :) More videos to come at some point soon.

@Edman_79 2 жыл бұрын

Very cool and unexpected! :D

@Metalliferous 2 жыл бұрын

Very interesting mods going way above and beyond the regular stuff here on KZfaq

@atheatos 2 жыл бұрын

Thank you! This was just a warm up. I will give you more like that in the future.

@djdjukic 2 жыл бұрын

Interesting results! Shame that the clock doubling does not work... Those CPU modules look slick, nice work as always.

@atheatos 2 жыл бұрын

Thank you :)

@angelgrig72 2 жыл бұрын

Παρα πολυ καλη δουλεια!

@atheatos 2 жыл бұрын

Thank you

@Kyriaki_Stergou_math_tools 2 жыл бұрын

Γεια σου βρε αθέατε με τα ωραία σου!

@atheatos 2 жыл бұрын

Thnx, oti mporo kano. O kathenas sto adikimeno tou ^^.

@johnprescott6614 2 жыл бұрын

thank you

@jannenilsson3627 2 жыл бұрын

Nice!

@distwaveps1 Жыл бұрын

I replaced several 386sx with 486SXLC2 some years ago and I found the same exact issue when enabling clock doubling on a Headland chipset based motherboard. On other motherboards the clock doubling worked fine and with a 33 MHz oscillator the chip overclocks to 66 MHz without issues.

@atheatos Жыл бұрын

Yeah this looks for sure like a chipset issue. I have more M/Bs to try now. Some with same chipset but later revision and some with other chipsets. We will see :)

@leoleonard1580 Жыл бұрын

Awesome stuff!! 'm working on upgrading an on 386sx luggable - would you be able to share where you got that 386sx breakout board? Can you share the design or can I get one from you?

@atheatos Жыл бұрын

If you have exactly the same M/B or with same interface it could be possible to use my implementation. Now for various reasons I can not and it is pointless to share my design. So if we establish you have a compatible M/B I can provide this for you. Just go to the store, hit contact and send me a message, include M/B info pics.

@DamienMC83 Жыл бұрын

Great video. I just purchased the same board and I'm interested in picking up a 486SXLC2 and attempting a similar mod. Would you be willing to share how you got the adapter PCB made? I'd love to build one for myself.

@atheatos Жыл бұрын

I am sorry but I can not share my designs. Even If I were to share designs, in general these are quite hard to build. If you are interested to buy an assembled and tested module like that, you can contact me though email.

@---cx9hd 5 ай бұрын

Any chance you can put up a link to the Cyrix software you used to control the processors you demonstrated? I have a TI 486SXLC and I haven't been able to find the proper software for controlling it's various functions.

@atheatos 5 ай бұрын

I added a link to a Vogons thread with what you are looking for. I might make a packet with everything for these Cyrix CPUs in the future. I just do not have these files not on my windows machine right now.

@jrherita 7 ай бұрын

Hmm the doubler failing bug showing the BIOS settings - curious if there is a Shadow RAM/ ROM enabled in the BIOS that is blocking the Cyrix app from writing to a memory location the CPU is looking for.

@atheatos 7 ай бұрын

Nice suggestion, I will check.

@marsupialpianist1450 3 ай бұрын

If fsb is 25 clock doubling should work but if higher cpu might force 1x. Maybe I forget and one version wanted to see 20fsb

@wskinnyodden 8 ай бұрын

Are you able to run Second Reality here? Or Unreal? With SBPRO compatible card. My SLC system was the most cursed PC I have had the luck of having. Kept crashing randomly on some software, and no it was not an hardware issue unless you count the CPU compatibility...

@atheatos 7 ай бұрын

I would try, not sure as I have never run these, probably ok. My system is stable.

@---cx9hd 4 ай бұрын

The limitation you were running into was that of the chipset. The RC2016A4 is limited to 40 MHz operation. It can accept up to 43 MHz apparently, but it will not allow for 50 MHz operation. That explains why you needed to hot plug the original 386 CPU to get past 43 MHz.

@atheatos 4 ай бұрын

Probably true. The clock doubler not working is probably the same thing too. I have a few M/Bs with the RC2016A5 chipset now. I might try there too. I have also some RC2016A5 chips I might try swapping chips.

@wskinnyodden 8 ай бұрын

That -cd test jumping into the BIOS is a behavior I had never seen before. How the heck did that cause the CPU to jump to some line on the BIOS ROM and resume from there instead of what the heck was supposed to happen?

@atheatos 7 ай бұрын

yeah, a very strange problem... I do not know probably incompatibility with the chipset, I will have to check on other motherboards too.

@dennisp.2147 2 жыл бұрын

Interesting... I have a Zenith 386SX16 desktop. It has an AMP socket that just allows you to swap the 386SX CPU. I stuck a 5v 486SLC in mine about ten years ago. The clock doubling worked out of the box on mine, but I was never able to get it to boot at a higher frequency than 16 mhz. So the machine is a 486SLC at 32 mhz

@atheatos 2 жыл бұрын

There is probably a strange incompatibility with my specific board and clock doubling. Now your report is very interesting. And yeah 32MHz is low. Clock doubling CPUs are only the 486SRx2 and the 486SXLC2. Also when you boot this is always disabled, you have to enable with config bit (Cyrix tool). 486SLC is not clock doubled, unless we are talking about an IBM 486SLC2. These are a totally different story and typically do not write 486SLC on top. So I am not sure on what exactly CPU you have. Maybe it is not a model with internal clock doubling. It will be interesting to know how you got clock doubling. or what exactly is written on your CPU.

@dennisp.2147 2 жыл бұрын

@@atheatos I may have misspoken, Mine is a clock-doubling chip. It's been a few years, so I don't remember exactly the part number. I'll have to look.

@distwaveps1 Жыл бұрын

@@atheatos And the Cyrix 486SLC2, in that one the clock doubling is always enabled

@atheatos Жыл бұрын

I think I do not have this one to test. At this point I do not even know what I have any more :/

@distwaveps1 Жыл бұрын

@@atheatos I feel your pain 🤣

@_bacterio Жыл бұрын

Will the CPU modules design be available or purchasable?

@atheatos Жыл бұрын

Thank you for the interest! This is somewhat already available. I have sold 1 or 2 of these. However I have not put this in the store as it is a very special adapter with limited compatibility. If you are interested you can go to the store and contact me. After we verify you have the same M/B or one looking 100% compatible we can arrange this.

@djpirtu2 Жыл бұрын

It's surprising how much slower SX-stuff is compared to DX. My first 386-PC was 386SX-33 back in 1993 and my friend had 386DX-40. At the time it was all about megahertz, nobody talked about data bus width. Just got myself a Toshiba T3200SX (386SX-16) and it's just soo sloow 😅 My tuned Toshiba T5200 with 486SXL2-40 wipes floor with it.

@atheatos Жыл бұрын

My first one was 386SX-40 probably in 1994 80MB HDD. Back then no one else had a PC and it looked fast to me either-way XD. And Yeah the difference surprised me too. Defiantly Bus bottlenecked. I now have a SX M/B with cache, so I will come back to to the topic to see if there is a difference.

@djpirtu2 Жыл бұрын

That'll be interesting to see! Just bought myself a 386-motherboard with 486DLC-33 on socket, MG-38606 and it has 256KB cache, UMC481. There's 66MHz oscillator and I have 80MHz one to put there but I think I have to buy any_clk from you to get everything out of it 🔥 Need to check do I have any 60ns SIMM or only 70ns... 🤔

@atheatos Жыл бұрын

Nice :) I want to get more M/Bs too. I have a few :) My fast Simm modules will also be back in stock soon :)

@djpirtu2 Жыл бұрын

@@atheatos Contacted you through the website for the any_clk and extra crystals 😃

@atheatos Жыл бұрын

Yeah I saw it thnx. I am sorry I am very busy these days, I will answer later today.

@run4restrun259 2 жыл бұрын

Good upgrade! :)) Now we need motherboard with 50Mhz and CPU with working doubler :)

@atheatos 2 жыл бұрын

Regarding 50MHz I am not sure if it is the M/Bs fault. I was able to run (somehow) the 386SX at 50. Regarding clock doubling, it looks like it works on some M/Bs it freezes on other. It is not only me. So yeah, I just need better luck next time.

@scottmm78 Жыл бұрын

If the only difference between 33 and 50 was one jumper could you in theory wire the "turbo" button to toggle it

@atheatos Жыл бұрын

In theory yes, this is possible. I am designing now a new thing that can do this even better. ^^

@alexloktionoff6833 7 ай бұрын

Great! Can you tell how I could get the boards and 486SXLC2 CPU? Are you interested to create PIstorm similar board /* use PIpico with local SRAM or PIzero */ for the 386SX M/B? Such CPU board could become ultimate upgrade - ARM uC could break 16Mb limit and emulate even 586 performance. Actually it could emulate even 686 and PIV, but the performance will be not equal

@atheatos 7 ай бұрын

I have never seen a board with an 486sxlc2 all ready soldered in. You can take any 386sx M/B and try a mod maybe. As for my mod / little adapter boards, I only sell these to very few people that have exactly my Model of M/B and the skills to solder. Regarding making an 486sxlc2 M/B with local SRAM chips for ram, yeah this is on my scope. It will be nice for sure. The main issue is to find a suitable chipset with a datasheet and no intergraded memory controller. Then the problem is the Bios. I can find solutions to all that but it will take time to design this.

@alexloktionoff6833 7 ай бұрын

I'd like to get your board and 486sxlc2 to challenge my soldering skills /*I have ALI M1217*/ Can I ?@@atheatos

@alexloktionoff6833 7 ай бұрын

But 486sxlc2 with local SRAM will not give enough boost, as 133MHz ARM or 166Mhz ESP. Amiga users made PIstorm, PC users also could... Is it possible to ignore the m/b bios /*there are few open-source bioses for QEMU/Bosh*/and DRAM controller and use only CPU pins to access ISA bus?@@atheatos

@atheatos 6 ай бұрын

So far I did not had the time to research this in depth but it looks like the main problem is the intergraded DMA + memory controller. If you put local Sram for RAM, then DMA transfers will still go to the memory controller. So I think this needs a barebone chipset like from the 286 era that do not intergrade a memory controller, Using the socket to just access the busses will not work (probably). Regarding performance difference it is very hard to tell, all 16bit bus 386, 486 chips are bottlenecked massively by the low bus thought put. So this could be probably performing up to a normal 486SX at same speed with Dram. I am just looking making my own mini boards in general, and this is one of the options. I need to check more the bios thing also, it is a bit outside my skills.

@alexloktionoff6833 6 ай бұрын

I also bought about it... so: #0 how 486SLC cache works then with DMA? There must be a solution to make SRAM on PIstorm board too #1 even if we have problems with #0 all RAM above 16Mb /*fast-ram*/ is not accessible by ISA DMA could be made SRAM without a problem, and 16MB DRAM on mother-board /*slow-ram*/ - similar like in AMIGA.@@atheatos

@Backwoods-Bob 2 жыл бұрын

I think that Cyrix made the chips for IBM.

@atheatos 2 жыл бұрын

Cyrix was fabless back then. They used other manufactures to produce they chips. They also license their designs to others to produce with their brands. These 486 386 replacement chips were also given to Texas Instruments. That is why the one I am using is branded as Ti486SXLC. In this generation IBM licensed the 486SLC form Intel! Probably a 486DX4 clone. For sure, later with 6x86 many were produced by IBM and some are even branded by IBM.

@mikeb3172 2 ай бұрын

There must have been a mix up in the factory about part numbers. I guarantee clock doubling works at 5v... they are 5v tolerant...

@atheatos 2 ай бұрын

The CPU is fine. For sure it supports clock doubling. The problem most likely here is an incompatibility of this clock doubling feature with the motherboard (with the M/B chipset or the bios). Others tried on the same M/B failed the same way, while this works on other M/Bs.

@channel4ferrets 2 жыл бұрын

Your shop checkout isn't working. I can put things in my cart but can't pay for it...

@atheatos 2 жыл бұрын

Thank you for the interest on my stuff. Yeah, Ordering directly from the store is not possible. The main reason is because I calculate shipping costs per case, individuality. The process, as it is also mentioned on item descriptions: -> To order send me a message. (Press "CONTACT" on the top of the page.) -> Just write your location and what you want. -> I am shipping worldwide! (From Europe - EU) -> I will calculate the shipping cost and send you the PayPal invoice. -> Shipping costs are combined for multiple Items.

@vladimirrodionov5391 5 ай бұрын

I don't believe Cyrix/TI/IBM "486"s have real 486 cores. They all licensed 386 from Intel and upgraded them with microprogrammed 486 isa and added cache. IBM I think manufactured them at lower nm which allowed them to boost the clock to 66 ands then 100mhz.

@atheatos 5 ай бұрын

Cyrix / TI ones did not license from Intel, but to my understanding these are their own 486 core just for 386 socket (they never had a 386). IBM is always confused with these but it is actually totally different. They licensed the 486 core directly from Intel. The pin out is mostly compatible with 386sx, but not 100% as there are extra pins regarding the cache (unfortunately undocumented). So unless the datasheet is found... or someone reverses a M/B with an IBM chip... modding one into a 386sx M/B with caches working is impossible.