I set a link to another ECS P5HX-A thread here:
ECS / Elitegroup P5HX-A L2 cache upgrade

Why? I notice, that the black passive cooler, which is located at top left on the board, gets extremly hot after playing some hours Quake 1 DOS or Quake 2 WIN with a K6-2 400, sometimes the system freezes.

According to gemini, it is necessary to put an active fan cooling to prevent damage.

Now I switched to my old P166MMX and decided that I will use it instead.

Nevertheless I m gratefull for the new bios, as I can use 128GB HDD or SDCARDs.

The overall stability is also great as it is i430HX chipset.

This will be my slowest Retro PC, I m using Phils Bootmenu along with slowest.bat and L2KILL.exe to slow it down to 386 level.

The current setup:

ECS P5HX-A
P166MMX
64MB EDO 60ns
Spea Mirage V7 2MB Trio64 PCI
Diamond Monster 3D V1 4MB PCI
Adaptec AH2940 with Teac CDR56S PCI
Intel 100 Network PCI
PicoGUS 2.0 ISA
Formosa 1670 ESS1868F ISA
AWE64 value ISA
DOS6.22/Win98SE dualboot

soon to arrive: Aliexpress USB 1.1 Adapter cable with only 5 Pins,which I will adapt to the old USB 1.1 settings of the i430HX era

soon to arrive: a cheap COAST 2.0 Module with extra 256KB Cache and an empty TAG SRAM Socket in order to plugin a Winbond SRAM which I bought from eBay and which works in the empty socket of the ECS.

In case the COAST 2.0 will not work, I will return it to the seller and will accept that this system can max. 64MB, which is more than enough for all games 1990...1997

Once again: as the ATX versions of Asus or Gigabyte i430 HX boards are very rare and expensive, I can recommend the ECS board as an ATX i430HX alternative if you want to build a P166MMX based Retro PC.

Hi eliot_new,

Thanks for the update.
A good call to switch back tot he P166MMX, you probably saved the linear regulator from burning-out. 😉

While running your K6-III/400 2.2V CPU previously, did you try if it became more stable with the System BIOS Cacheable option disabled? Just curious.

Cheers, Jan

eliot_new wrote on 2026-08-09, 14:20:

I set a link to another ECS P5HX-A thread here: ECS / Elitegroup P5HX-A L2 cache upgrade […]
Show full quote

I set a link to another ECS P5HX-A thread here:
ECS / Elitegroup P5HX-A L2 cache upgrade

Why? I notice, that the black passive cooler, which is located at top left on the board, gets extremly hot after playing some hours Quake 1 DOS or Quake 2 WIN with a K6-2 400, sometimes the system freezes.

According to gemini, it is necessary to put an active fan cooling to prevent damage.

Now I switched to my old P166MMX and decided that I will use it instead.

Nevertheless I m gratefull for the new bios, as I can use 128GB HDD or SDCARDs.

The overall stability is also great as it is i430HX chipset.

This will be my slowest Retro PC, I m using Phils Bootmenu along with slowest.bat and L2KILL.exe to slow it down to 386 level.

The current setup:

ECS P5HX-A
P166MMX
64MB EDO 60ns
Spea Mirage V7 2MB Trio64 PCI
Diamond Monster 3D V1 4MB PCI
Adaptec AH2940 with Teac CDR56S PCI
Intel 100 Network PCI
PicoGUS 2.0 ISA
Formosa 1670 ESS1868F ISA
AWE64 value ISA
DOS6.22/Win98SE dualboot

soon to arrive: Aliexpress USB 1.1 Adapter cable with only 5 Pins,which I will adapt to the old USB 1.1 settings of the i430HX era

soon to arrive: a cheap COAST 2.0 Module with extra 256KB Cache and an empty TAG SRAM Socket in order to plugin a Winbond SRAM which I bought from eBay and which works in the empty socket of the ECS.

In case the COAST 2.0 will not work, I will return it to the seller and will accept that this system can max. 64MB, which is more than enough for all games 1990...1997

Once again: as the ATX versions of Asus or Gigabyte i430 HX boards are very rare and expensive, I can recommend the ECS board as an ATX i430HX alternative if you want to build a P166MMX based Retro PC.

You don't happen to have a driver disc for the Teac CD-R56S do you?
I'm trying to install OS/2 via the same type of drive, but I simply cannot find a driver for it.

Chkcpu wrote on 2026-08-10, 09:15:

Hi eliot_new, […]
Show full quote

Hi eliot_new,

Thanks for the update.
A good call to switch back tot he P166MMX, you probably saved the linear regulator from burning-out. 😉

While running your K6-III/400 2.2V CPU previously, did you try if it became more stable with the System BIOS Cacheable option disabled? Just curious.

Cheers, Jan

Dear Jan, I m sorry for answering you that late.

Now I installed once again the K6-3 nonplus 400.

2x multi with 66Mhz = 398 Mhz with 2.5Voltage

System BIOS Cacheable option disabled as well as Video Bios Cachable disabled as well as Video Bios Shadow disabled

Results: (1) DOS 6.22 boots fine, Q1 software mode runs fine (2) Win98SE boots ok, but as soon as I start a game like Q2, HL1, Tomb Raider 1 or Baldurs Gate I get immedately a system freeze.

This means: I can finally confirm, that with your Bios the maximum CPU is a K6-2 / 400 but the black Mainboard heatsink must be cooled very well actively in order to prevent crashes after long gaming.

Furthermore I discovered, that even if you use an old USB 1.0 Adapter, the USB header it self is faulty and cannot be used in Win98SE (no matter which Intel driver I installed, always yellow question mark).

This means, if you want USB on ECS P5HX-A, you must sacrifice a PCI slot with an ALi 1573 USB 2.0 Card.

LunarG wrote on 2026-09-03, 18:32:

eliot_new wrote on 2026-08-09, 14:20:

I set a link to another ECS P5HX-A thread here: ECS / Elitegroup P5HX-A L2 cache upgrade […]
Show full quote

I set a link to another ECS P5HX-A thread here:
ECS / Elitegroup P5HX-A L2 cache upgrade

Why? I notice, that the black passive cooler, which is located at top left on the board, gets extremly hot after playing some hours Quake 1 DOS or Quake 2 WIN with a K6-2 400, sometimes the system freezes.

According to gemini, it is necessary to put an active fan cooling to prevent damage.

Now I switched to my old P166MMX and decided that I will use it instead.

Nevertheless I m gratefull for the new bios, as I can use 128GB HDD or SDCARDs.

The overall stability is also great as it is i430HX chipset.

This will be my slowest Retro PC, I m using Phils Bootmenu along with slowest.bat and L2KILL.exe to slow it down to 386 level.

The current setup:

ECS P5HX-A
P166MMX
64MB EDO 60ns
Spea Mirage V7 2MB Trio64 PCI
Diamond Monster 3D V1 4MB PCI
Adaptec AH2940 with Teac CDR56S PCI
Intel 100 Network PCI
PicoGUS 2.0 ISA
Formosa 1670 ESS1868F ISA
AWE64 value ISA
DOS6.22/Win98SE dualboot

soon to arrive: Aliexpress USB 1.1 Adapter cable with only 5 Pins,which I will adapt to the old USB 1.1 settings of the i430HX era

soon to arrive: a cheap COAST 2.0 Module with extra 256KB Cache and an empty TAG SRAM Socket in order to plugin a Winbond SRAM which I bought from eBay and which works in the empty socket of the ECS.

In case the COAST 2.0 will not work, I will return it to the seller and will accept that this system can max. 64MB, which is more than enough for all games 1990...1997

Once again: as the ATX versions of Asus or Gigabyte i430 HX boards are very rare and expensive, I can recommend the ECS board as an ATX i430HX alternative if you want to build a P166MMX based Retro PC.

You don't happen to have a driver disc for the Teac CD-R56S do you?
I'm trying to install OS/2 via the same type of drive, but I simply cannot find a driver for it.

AFAIK you don't need a driver for the Teac CD-R56S.
You need only a driver for your SCSI controller.
For instance I have an Adaptec AHA2940 USCSI:
https://theretroweb.com/expansioncards/s/adaptec-aha-2940
If I wanted to install OS/2 I d search for an OS/2 driver for my Adaptec.

Btw: I like your signature, we have similar 3x Retro PCs

@OP; Did you ever run with motherboard L2 disabled? For the k6-3 it might solve your problem. The motherboard L2 cache is no longer needed. And you would be able to cache all available RAM with the k6-3 L2. You could try a lower multiplier for the k6-3 to see if it’s more stable. I ran my k6-3 400 as low as 233MHz on my MS-5158 430tx board for direct comparison with Pentium 233MMX

FullYes wrote on 2026-09-17, 19:08:

@OP; Did you ever run with motherboard L2 disabled? For the k6-3 it might solve your problem. The motherboard L2 cache is no longer needed. And you would be able to cache all available RAM with the k6-3 L2. You could try a lower multiplier for the k6-3 to see if it’s more stable. I ran my k6-3 400 as low as 233MHz on my MS-5158 430tx board for direct comparison with Pentium 233MMX

Just tried it out. Guess what? Even worse,Win98SE crashes immediately. I think it is ok, that one can run max. K6-2 400 2.2V. This limits the RAM to max 64MB but most of the games till 1998 run fine. Once again I m very gratefull for Jan Steunebrinks work!

eliot_new wrote on 2026-09-19, 12:05:

FullYes wrote on 2026-09-17, 19:08:

@OP; Did you ever run with motherboard L2 disabled? For the k6-3 it might solve your problem. The motherboard L2 cache is no longer needed. And you would be able to cache all available RAM with the k6-3 L2. You could try a lower multiplier for the k6-3 to see if it’s more stable. I ran my k6-3 400 as low as 233MHz on my MS-5158 430tx board for direct comparison with Pentium 233MMX

Just tried it out. Guess what? Even worse,Win98SE crashes immediately. I think it is ok, that one can run max. K6-2 400 2.2V. This limits the RAM to max 64MB but most of the games till 1998 run fine. Once again I m very gratefull for Jan Steunebrinks work!

Yeah me too! He did a bios for my board as well. Works great!