Passively cooling an AMD K6

Sean Fox · 3 Jan 2020 at 10:57

I’m currently running an old Gateway 2000 system for my Win98SE retro gaming rig. It’s all based around a Pentium 200MMX, which is passively cooled.

I’ve just picked up an AMD K6-266AFD (it's not a K6-2) which I’m going to swap in for a performance increase. Would I be able to use the same heatsink or will I need to look at a heatsink+fan combination?

Armageus · 3 Jan 2020 at 11:43

Wouldn't have thought it would be a problem, power dissipation if anything is better for the K6 (15.4w vs 18.87w Max for the MMX)

http://www.cpu-world.com/CPUs/Pentium/Intel-Pentium MMX 200 - A80503200.html
http://www.cpu-world.com/CPUs/K6/AMD-K6 300 - AMD-K6-300AFR.html

Sean Fox · 3 Jan 2020 at 11:47

Armageus said:
Wouldn't have thought it would be a problem, power dissipation if anything is better for the K6 (15.4w vs 18.87w Max for the MMX)

http://www.cpu-world.com/CPUs/Pentium/Intel-Pentium MMX 200 - A80503200.html
http://www.cpu-world.com/CPUs/K6/AMD-K6 300 - AMD-K6-300AFR.html

Awesome - thanks mate! That's what I thought, but I just wanted to get a second opinion (and some reassurance that wasn't being a complete idiot

)

Alan1969 · 4 Feb 2020 at 16:48

I think that they were all passively cooled back in the day. I remember cpus that didn't even have heat sinks on them. My friend overclocked his cpu that didn't have a heat sink by leaving the case off and having a room fan roughly point in that direction.

Alan1969 · 4 Feb 2020 at 16:50

I remember the gateway 2000 advertising of a friesand cow (black and white spots). I nearly bought a dx33 gateway.

Cyber-Mav · 13 May 2020 at 21:45

Doubt you will get a performance boost. Anything other than intel of that time period had a very weak floating point unit. My old cyrix 586 was lame too

paradigm · 14 May 2020 at 07:01

Cyber-Mav said:
Doubt you will get a performance boost. Anything other than intel of that time period had a very weak floating point unit. My old cyrix 586 was lame too

I think you do the K6 family a disservice, its FPU was massively faster than that in the (quite frankly terrible) Cyrix. In most cases FPU performance was around 90-95% clock for clock of a Pentium MMX (and ALU performance was notably better than Intel), most K6 CPUs ran FASTER clock speeds than the Pentium as development of the Pentium was being phased out in favour of the Pentium II and Slot 1. This brought the need for Super Socket 7 which was spearheaded by AMD and the rest of the consortium of Intel clone manufacturers.

Cyber-Mav · 14 May 2020 at 08:29

Was that the cpu that had 3dnow instructions?

paradigm · 14 May 2020 at 08:35

K6-2 and up had 3dnow, it was comparable to SSE on the Pentium III, but had to be specifically coded into the application to see a benefit.

Quake 2 with the patch for example sees around a 40% uplift in software rendering when enabling 3dnow!

GeX · 14 May 2020 at 09:02

Who was using software rendering by then though?

(I do have a selection of K6 chips, Inc some III+s )

paradigm · 14 May 2020 at 09:22

There were also 3dnow enhanced renderers for 3dfxGL and OpenGL, I'm not sure on the % uplift on those though.

Duke · 14 May 2020 at 17:27

I had a K6-2 back in the day, great chip at the time. I can't remember what clock speed it was though, either 400 or 500 I think. 3DNow ftw.