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Cachechk stalls on 80486 Cyrix CPUs

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First post, by Masejoer

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I have a MV035 motherboard here (actually two, both behave the same) and can run cachechk (v4 2/7/96) on Intel and AMD CPUs (33-100MHz), but my Cyrix 486 DX4-100 and 5x86-100GP CPUs both stall out in cachechk when on line/Megabyte "3." Only a reboot gets the system responding again. I didn't find anything online about this, and apparently none of my other socket 3 boards support (won't even POST) these Cyrix processors. Is this my board causing this, or does this test not work on Cyrix chips? More below.

In additional notes, my ISA POST code card switches to "d2" when both of these Cyrix CPUs get to that point of the program. The other Intel and AMD CPUs show the same FF from the end of POST. Cachechk on both MV035 motherboards running non-Cyrix CPUs state that "it looks like megabyte #3 isn't being cached", the same line that the Cyrix CPUs get stuck on. Other than this 3rd Megabyte, It shows that cache is running fine. Same program output on both boards and different CPUs, re-using the RAM.

The motherboard is running with 4x16MB 30-pin SIMMS and 256KB of L2 cache.

Lastly, 3D bench stops rendering after a couple minutes on Cyrix, but loops forever with both the AMD and Intel chips. It seems like the Cyrix chips may be "unstable" once I get the HDD situation sorted. The 14 CPU and frequency Jumpers and two for Voltage are all set correctly, following https://stason.org/TULARC/pc/motherboards/D/D … -BUS-MV035.html

Any ideas or input on the Cyrix CPU behavior? I can't blame the CPUs now that I can see two different Cyrix chips behaving the same way.

----

And for a question unrelated to the Cyrix - I also cannot get a CF adapter to work (no POST) via two different ISA controller cards when using this motherboard model, so right now my testing is from floppy boot...the system is a bit of a pain to use like this. I get one long and three short beeps after the IDE to CF adapter is hooked up to my controller card(s) and powered via floppy power plug. It's hooked up correctly - I've been using these adapters and controller cards in various boards since last year. My IDE to SATA adapters are packed away and I don't have any old, small IDE mechanical drives to hook up. I've changed the address jumpers on one controller with no luck, and the second one isn't configurable. A different videocard didn't change this behavior either (this is what one long, three short should be related to). Not sure what's up here, but perhaps someone has experienced similar no-POST after a CF adapter is attached to controller card.

Last edited by Masejoer on 2021-12-13, 06:51. Edited 1 time in total.

Reply 1 of 8, by debs3759

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Masejoer wrote on 2021-12-13, 06:14:

The motherboard is running with 4x16GB 30-pin SIMMS and 256KB of L2 cache.

4 x 16GB on a 486? I guess you mean 4 x 16MB 😀

Can't help with your question though, sorry.

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 2 of 8, by Masejoer

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debs3759 wrote on 2021-12-13, 06:39:
Masejoer wrote on 2021-12-13, 06:14:

The motherboard is running with 4x16GB 30-pin SIMMS and 256KB of L2 cache.

4 x 16GB on a 486? I guess you mean 4 x 16MB 😀

Can't help with your question though, sorry.

Errrr, yeah. I only have four matching 30-pin sticks of 16MB, so testing with a crazy 64MB of RAM on a 486. More appropriate would be about 4x2MB 😉 According to the motherboard's configuration page, 4x16MB sticks aren't even "supported", but it seems to work with Intel and AMD CPUs fine.

My 90's 486 DX4-100 had a whopping 4x1MB and 4x256KB simms back then - I believe I ran that thing at 5MB until upgrading to a K6-300 with 32MB of RAM.

Last edited by Masejoer on 2021-12-13, 06:57. Edited 2 times in total.

Reply 3 of 8, by BitWrangler

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But if we add PAE to a 486 somehow to break the 4GB barrier....

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 4 of 8, by Masejoer

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As an update, I found some odd behavior with the board and (default) BIOS sleep timer. The 15-second setting appears to correlate with cachechk reaching the 3rd Megabyte of RAM. Perhaps Cyrix chips don't handle the implemented sleep timer. Disabling this BIOS setting did get rid of "it looks like megabyte #3 isn't being cached" on the Intel 33 chip I have in there now. Will test Cyrix later.

This was the issue with cachechk all along. I guess I do need to check power management settings on all the old boards. Haven't touched those in such a long time in any system.

CF card, the motherboard wanted the controller card's jumper set to cable select. Not sure what "ALE" is instead of cable select, but that other default jumper "ALE" setting works on all my other boards. Not this one, apparently.

Happily chugging away from a DOS CF card now. I really need to get some 72 pin FPM memory to use in this thing - only have 30 pin, and EDO 72. I don't remember DOOM running so well on an Intel DX 33, or even my dad's DX2-66/paradise vlb setup back in the day.

Edit: Cyrix 5x86 works fine now also. I'm being bottlenecked by the ISA graphics card in there though - doom runs about 2fps faster than the DX-33 chip 😉

Last edited by Masejoer on 2021-12-13, 23:30. Edited 1 time in total.

Reply 5 of 8, by debs3759

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Masejoer wrote on 2021-12-13, 19:11:

Not sure what "ALE" is,

ALE is proper beer, for those who think lager is just flavoured water.

<Sorry, I couldn't resist that 😀 >

Glad you resolved the problem.

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 6 of 8, by douglar

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Masejoer wrote on 2021-12-13, 19:11:

Happily chugging away from a DOS CF card now. I really need to get some 72 pin FPM memory to use in this thing - only have 30 pin, and EDO 72. I don't remember DOOM running so well on an Intel DX 33, or even my dad's DX2-66/paradise vlb setup back in the day.

Edit: Cyrix 5x86 works fine now also. I'm being bottlenecked by the ISA graphics card in there though - doom runs about 2fps faster than the DX-33 chip 😉

Pretty sure ISA graphics card hits you two ways.

First it's slow to push pixels. Second, a socket 3 CPU isn't doing anything else while pushing pixels, so every ISA cycle ends up eating multiple CPU cycles as the processor waits for the IO to clear.

But Doom was playable for me on a fast ISA card back in the day.

Reply 7 of 8, by Masejoer

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douglar wrote on 2021-12-14, 19:55:

But Doom was playable for me on a fast ISA card back in the day.

Hah! Back then, 5fps was "playable" for many games to me, and 10-15 on later riva 128 cards in some hardware accelerated games was amazing/"buttery smooth". I may still have a computer magazine in a box that showed how fast a 15fps framerate was compared to the competition. I remember "playing" destruction derby at 1-2fps on a DX2, but upper single digits were fully playable by comparison. Just think Quake - a lot of us were still using a 486 when Quake was released, but we enjoyed it anyway. 😉

Our standards sure have changed since then! The 486 did a lot of things at single digits, but we still played it.

Reply 8 of 8, by debs3759

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douglar wrote on 2021-12-14, 19:55:

But Doom was playable for me on a fast ISA card back in the day.

I was doing a software engineering course in 1995. I remember the day one of the lads brought in a brand new Pentium laptop, and everyone was in awe at how smooth Doom was on it. I'm looking forward to playing doom on a Cyrix and an AMD 5x86 when I finish reorganising my collection (feels like that's taking forever! An hour of moving boxes around and I need to rest for a week 😀 )

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

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