Write allocate is a setting on the CPU that you can toggle regardless of chipset. Whether it's faster on or off depends on the application. Games that do software rendering are usually faster with it off, so that framebuffer writes don't cause unnecessary reads/thrashing.
Linear Burst was only supported on some chipsets. Maybe someone here knows exactly what it was, but I don't think it made a huge difference. I seem to recall that it was something Cyrix did differently than Intel just to avoid patent infringement.

Some makers managed to work some optimisations into the BIOS on intel boards but they were at risk of incurring Intel's petty wrath and losing priority on Intel chipsets and tech info, so maybe didn't put too much effort into it. However, another thing to remember to wring the best out of a Via board is to use DIMM compatible with the 4x bank interleave feature.

Many non-intel chipsets handled 75mhz+ FSB much better, some of the sis motherboards had 33mhz async PCI which only works with Cyrix.

From what I remember only one board was 75mhz FSB certified at the pr200 launch

bakemono wrote on 2026-10-28, 02:08:

Write allocate is a setting on the CPU that you can toggle regardless of chipset. Whether it's faster on or off depends on the application. Games that do software rendering are usually faster with it off, so that framebuffer writes don't cause unnecessary reads/thrashing.

I'm not even sure Write Allocate was a Cyrix thing or more of a K5 or K6 option in the BIOSes of the era. Good to know regardless.

BitWrangler wrote on 2026-10-28, 02:20:

Some makers managed to work some optimisations into the BIOS on intel boards but they were at risk of incurring Intel's petty wrath and losing priority on Intel chipsets and tech info, so maybe didn't put too much effort into it. However, another thing to remember to wring the best out of a Via board is to use DIMM compatible with the 4x bank interleave feature.

Good catch. Was 4-way Bank Interleaving a thing in VIA chipsets all the way back in 1996/1997? I thought it was more of a Apollo Pro133/Pro133A thing and later.

rmay635703 wrote on Yesterday, 00:38:

Many non-intel chipsets handled 75mhz+ FSB much better, some of the sis motherboards had 33mhz async PCI which only works with Cyrix.

From what I remember only one board was 75mhz FSB certified at the pr200 launch

I'm leaning towards this as well, that the recommendations came because of better support for the 75MHz and latter 83MHz FSB, rather than any specific BIOS/chipset feature that unlocked some "super secret ultimate performance mode" on the processors. That being said, I've had exceptionally good experiences running all my 430VX and 430TX boards at 75MHz, even if the PCI bus likely gets a bit overclocked. Some people even swear by 83MHz on these boards, but I haven't had good experiences with that. And Super 7 boards essentially make this a moot point today, if you want to run Cyrix processors with weird FSBs you can just grab one of them.

I think the reason I made this thread and kept thinking about the subject is that I always see people comparing Cyrix CPUs with Intel ones from the era and they all do it on the same platform, which makes sense, it's convenient and saves a great deal of time, but it's also kind of paradoxical in the sense that I've read so many conflicting reports that Cyrix CPUs were really undermined when not run on a VIA or SiS chipset or something. Which in itself doesn't make a ton of sense, given that chipsets other than Intel's at the time were not as fast and definitely not as stable as Intel's (at least in certified settings, such as 66MHz FSB).

What I'm getting at is that maybe those features did in fact give the Cyrix processors a performance boost, but overall performance of 430VX and HX chipsets likely made up most of the difference, to the point where it didn't make much sense not to go with them instead of VIA/SiS/ALi/etc. Just strange that I can't seem to find a single thread here on VOGONS comparing performance across 2 or 3 different chipsets.

Thank you for the answers so far.

Garrett W wrote on Yesterday, 08:39:

Good catch. Was 4-way Bank Interleaving a thing in VIA chipsets all the way back in 1996/1997? I thought it was more of a Apollo Pro133/Pro133A thing and later.

It appeared in the VP series. See these notes for an enabler util if the BIOS forgot to add it...
https://soggi.org/files/misc/tools/Memory-Int … bler-readme.htm (link at top of page takes you to the utility download page to find it)
Some enabled/disabled benchmark results given there.

Then also in the FIC motherboards page at DOSdays, it is mentioned that the PA-2010 needs it disabled at 83Mhz, and that is a VPx. So not sure if it was new to the VPx and whether it's FIC or Via's fault it doesn't work at 83mhz on that board.

I always heard it needed 64Mbit chip on the SDRAM to enable 4 bank interleave but that page above says the driver will still enable on 16Mbit, but not sure whether it is cautioning not to because the driver doesn't have a check, or pointing out that with only 2 banks per chip you'll need 2 modules for it to work instead of 1+ with 64Mbit.

Edit: actually would be interesting to see if the PA-2010 just has a boot/POST glitch and that driver still works at 83 if you leave it unset in CMOS setup.

Kowalski! Analysis?
https://www.vogonswiki.com/index.php/Super_So … et_7_Benchmarks

I think those tables might give us a few clues but will have to look at it later unless anyone beats me.

I've run the IBM/cyrix 6x86 CPUs on a few different boards including the 430VX and 430TX, and I think they mainly benefit from bus speed. Later socket 7 boards with higher bus speeds typically used chips from VIA, SiS and Ali. This may be what you're referring to? The newer chips set to low speed seem to be about the same as older ones. If there's some test in particular that you're interested in, I can try to check it. For an example, try a 6x86 at 200MHz (2x100) vs 210MHz (3.5x60).

The 6x86L has less cache and is particularly helped with higher bus speed. The 6x86M has a larger cache and can keep up with the K6-2. The full speed, on-die cache of the K6-3 and "plus" CPUs seems to be the best help for slower bus speeds.

BitWrangler wrote on Yesterday, 12:26:

It appeared in the VP series. See these notes for an enabler util if the BIOS forgot to add it... https://soggi.org/files/misc/t […]
Show full quote

It appeared in the VP series. See these notes for an enabler util if the BIOS forgot to add it...
https://soggi.org/files/misc/tools/Memory-Int … bler-readme.htm (link at top of page takes you to the utility download page to find it)
Some enabled/disabled benchmark results given there.

Then also in the FIC motherboards page at DOSdays, it is mentioned that the PA-2010 needs it disabled at 83Mhz, and that is a VPx. So not sure if it was new to the VPx and whether it's FIC or Via's fault it doesn't work at 83mhz on that board.

I always heard it needed 64Mbit chip on the SDRAM to enable 4 bank interleave but that page above says the driver will still enable on 16Mbit, but not sure whether it is cautioning not to because the driver doesn't have a check, or pointing out that with only 2 banks per chip you'll need 2 modules for it to work instead of 1+ with 64Mbit.

Interesting, one more thing to try I guess if I eventually start doing some tests. I've just had a look and both FIC PA-2010 (VP1 based) and PA-2007 (VP2 based) have a jumper next to the cache chips that can be jumpered for Intel Burst or Linear Burst, so I'm thinking @bakemono might be onto something about the way Intel did things was patented.

As for the benchmarks for the VOGONS wiki page, I don't think they are especially helpful for what I am trying to discern.

nickles rust wrote on Yesterday, 22:23:

I've run the IBM/cyrix 6x86 CPUs on a few different boards including the 430VX and 430TX, and I think they mainly benefit from bus speed. Later socket 7 boards with higher bus speeds typically used chips from VIA, SiS and Ali. This may be what you're referring to? The newer chips set to low speed seem to be about the same as older ones. If there's some test in particular that you're interested in, I can try to check it. For an example, try a 6x86 at 200MHz (2x100) vs 210MHz (3.5x60).

The 6x86L has less cache and is particularly helped with higher bus speed. The 6x86M has a larger cache and can keep up with the K6-2. The full speed, on-die cache of the K6-3 and "plus" CPUs seems to be the best help for slower bus speeds.

No, I'm not talking about the bus speed, I think it's fairly easy to understand how this would affect things. I've seen posts and magazine articles recommending VIA boards instead of Intel ones even for CPUs using the 66MHz FSB such as the PR166.

If you have a 430VX or TX board and a VP1 or VP2 board and are willing to do a couple of benchmarks I'd be grateful! I would maybe compare a classic PR166 (L variant or not shouldn't matter) on both boards and see if the BIOS on the VIA side has any options relating to the Cyrix CPU.

Garrett W wrote on Today, 09:13:

As for the benchmarks for the VOGONS wiki page, I don't think they are especially helpful for what I am trying to discern.

Damn yeah, giving them a thorough look there's almost no results for Machine 4 which would be our Intel TX baseline, then all the others barely have one CPU speed that matches another and the Via machines barely have any numbers there either.

This article would be fairly informative, apart from I can't be assed subscribing to Toms now they put that fence up...
https://www.tomshardware.com/reviews/review-s … rboards,46.html

However, it seems like there's less than a whole percent between best 430TX board and the best VP2 board in this graphic, the x axis cut off at 65 so exaggerated spread there's less than 4% between top and bottom.

I wouldnt believe anyone recommending non Intel socket7 chipset. Especially when combined with PB cache Intel could be up to 20-30% faster than some popular because cheap at the time VIA/SIS abominations https://dependency-injection.com/early-pentium-chipsets/
Im not familiar with any Intel chipset having problems at 75MHz, and afaik 83MHz gave only problems with some disks (writes) when mobo clock gen didnt support Async PCI clock 33MHz output.