Retro upgrade from K6-III to K6-III+

[Comos]

Hi everyone,

this thread is a little bit retro, but I can't figure out where is the problem.

I recently run my older PC with ASUS TX-97-X which has patched BIOS to support AMD K6 CPU's.

Most of the time I run a K6-III 400 clocked @ 412Mhz (5.5x75).Somehow this one didn't run stable at 450.Half year ago I got a few AMD K6-III+ 400.

When I install this CPU, I clocked it to 450 (6x75), runs stable, but when tested quickly in MPXPLAY, the CPU load is about 2-3% higher then I had with K6-III which was clocked even lower !

The tools that runs under DOS to get max from this CPU I run all the time, but what could be the problem? The stepping of the CPU or the PowerNow! feature is throttling the performance?

[submix8c]

http://www.cpu-world.com/CPUs/K6-III/index.html

Have you tried clocking at 5.5x (the lower)?

Hmmm. according to the above, you might have a K6-IIIE+ (different FSB) @4x100. And you didn't mention whether the K6-III was 66 or 100 FSB.

Bus speed matters. IMHO it's better to go a higher FSB than a higher multiplier (which depends on the CPU and the MoBo abilities). IOW, choosing a "slower" CPU that uses a higher FSB MIGHT run faster - or even an "equivalent" speed (as you might have).

[Comos]

http://www.cpu-world.com/CPUs/K6-III/index.html

Have you tried clocking at 5.5x (the lower)?

Hmmm. according to the above, you might have a K6-IIIE+ (different FSB) @4x100. And you didn't mention whether the K6-III was 66 or 100 FSB.

Bus speed matters. IMHO it's better to go a higher FSB than a higher multiplier (which depends on the CPU and the MoBo abilities). IOW, choosing a "slower" CPU that uses a higher FSB MIGHT run faster - or even an "equivalent" speed (as you might have).

I have tried once only to test if the mobo will bootup with K6-III+, then I set it to 6.0x.The previous K6-III was AMD-K6-III/400AFR.Now the AMD K6-IIIE+ 400 - K6-III+/400ATZ.

Seems you are right about the FSB as I checked both CPU's.On both the 75Mhz remained in my setup.

[dencorso]

Did you visit Jan Steunebrink's Getting the AMD K6-2+ / K6-III+ to work on your Super Socket 7 board page?

[submix8c]

Ouch!

According to Rev.3.0 MoBo manual that's the best you'll get - Voltage 2.1v / 6x75mhz=450mhz.

Sad... I dumped 2 Tyan S1590's recently for recycle. If I'd still had them, I would have gladly given you one (gratis).

[Comos]

Did you visit Jan Steunebrink's Getting the AMD K6-2+ / K6-III+ to work on your Super Socket 7 board page?

Sure, I had a long chat with Jan about the patching and had a last custom patch installed.

[Comos]

Ouch!

According to Rev.3.0 MoBo manual that's the best you'll get - Voltage 2.1v / 6x75mhz=450mhz.

Sad... I dumped 2 Tyan S1590's recently for recycle. If I'd still had them, I would have gladly given you one (gratis).

The official MoBo manual doesn't tell all the secrets.I tested all combinations and the lowest volatge I can get is 2.0V.

To get 450Mhz is fine for me,but not with less CPU power that I had before,which disappoints me.

I have a revision v2.3, the board I have fixed with newer and stronger FET's to handle newer CPU's.Interesting is, that there are other types like TX97-E which supports also 83Mhz FSB, look similar like T97-X but on T97-X that FSB combination doesn't work.

Dunno why Asus didn't impletent it to the T97-X which seemed was the last in their series with Triton II chipset.