Did you set the jumpers correctly? "cpu however seems to perform identical to the 233mhz mmx" would indicate it's set up at 66x3.5. You should be able to run it at 2x66, yielding 400MHz (K6 CPUs interpret 2x as 6x internally).

kanecvr wrote:

Did you set the jumpers correctly? "cpu however seems to perform identical to the 233mhz mmx" would indicate it's set up at 66x3.5. You should be able to run it at 2x66, yielding 400MHz (K6 CPUs interpret 2x as 6x internally).

But isn't it odd that the K6-2/266 didn't post at all?
That CPU and the K6-2/450 should have similar CPU voltages. Perhaps it's something to do with the 450 being Chompers and the other possibly not being a Chompers?

And kanecvr is right about the K6-2/450 going 6x multi when set to 2x, this 'trick' was kinda popular to help speed up non-super s7 boards that could run 2.2v voltages 😀

ok i set the multiplier at 2x. theres also a vcc jumper which can be set to 2.8v 3.3v and 3.5v. it's set to 2.8v should it be higher?

No, it should be even lower (but it can work at 2.8, you just need a good cooler)

emosun wrote:

ok i set the multiplier at 2x. theres also a vcc jumper which can be set to 2.8v 3.3v and 3.5v. it's set to 2.8v should it be higher?

I don't recommend long-term operation at 2.8 on a k6. It needs 2.2v (or 2.4 in case of some chips).

There isn't a 2.2v option. i did notice the cpu says 3.3v on it. from what i can feel the cpu heatsink isnt even hot , it's got a socket 370 cooler.

Is there decent cpu benchmarking program like cinebench but for windows 98. may help to see just some baseline numbers to see what each change does.

kanecvr wrote:

emosun wrote:

ok i set the multiplier at 2x. theres also a vcc jumper which can be set to 2.8v 3.3v and 3.5v. it's set to 2.8v should it be higher?

I don't recommend long-term operation at 2.8 on a k6. It needs 2.2v (or 2.4 in case of some chips).

My IBM aptiva originally came with a pmmx 233, but when I got it, it had a K6-2 500 with the mmx specs, so 2.8v and 233MHz so pretty munch an useless upgrade. It was probably fine for all these years, but like you, I won't recommend it either for longt term use

emosun wrote:

There isn't a 2.2v option. i did notice the cpu says 3.3v on it. from what i can feel the cpu heatsink isnt even hot , it's got a socket 370 cooler.

Is there decent cpu benchmarking program like cinebench but for windows 98. may help to see just some baseline numbers to see what each change does.

!!!! 3.3 is for I/O!!!! not for vcore!! the K6-II is a dual voltage chip, just like the pentium MMX, but unlike the pentium MMX it needs 2.2v, 2.4 tops. No higher. If your board can't do 2.2v get an interposer or give up on the idea of using a K6 in it.

ok I ran a few bench tests of the p1 233 and the k6-2 450 and it seems to be working very well. When set to the 2x multiplier it does go much faster than with the 3x multiplier. I found an old version off passmark which is very thorough. But i did notice the machine can handle most bitrate in video playback with it as well.

Deksor wrote:

My IBM aptiva originally came with a pmmx 233, but when I got it, it had a K6-2 500 with the mmx specs, so 2.8v and 233MHz so pretty munch an useless upgrade. It was probably fine for all these years, but like you, I won't recommend it either for longt term use

Yeah I think the cpu most likely can handle the 2.8v increase. It's really not even running hot , or even slightly warm for that matter. Most likely it's not really being pushed very hard.

I have the K6-2 500MHz, actually running at lowest clock 166MHz. It's core voltage is 2.2V, and I/O voltage 3.3V (like kanecvr said, dual voltage).
I' ve still set the voltage to default (auto) voltage.

Personally, i would never set the voltage to high values, especially for descent old cpu's.

Even when you can keep it cool, you have to consider the "Electromigration" when running with high voltage beyond the specifications of AMD.

According to amd the absolute maximum voltage for the k6-2 is 2.5V and anything above that will for sure damage the cpu. It's a well known fact that after some time the cpu stops working at its default voltage and speed but it would take very long to kill the cpu.

dondiego wrote:

According to amd the absolute maximum voltage for the k6-2 is 2.5V and anything above that will for sure damage the cpu. It's a well known fact that after some time the cpu stops working at its default voltage and speed but it would take very long to kill the cpu.

Still I think it's a waste frying such a chip simply because one fails to relocate a jumper or 2.

emosun, like some have already mentioned, s7 uses split CPU voltage (even Pentium MMX uses split voltage and newer s7/ss7 chips need even lower voltages).

What's the model number of your board?
Could you supply us with a pic of your board along with its jumper settings? Perhaps your board actually does support lower voltages as many boards have hidden or unofficial jumper settings.

dondiego wrote:

According to amd the absolute maximum voltage for the k6-2 is 2.5V and anything above that will for sure damage the cpu. It's a well known fact that after some time the cpu stops working at its default voltage and speed but it would take very long to kill the cpu.

^this

http://www.uktsupport.co.uk/pb/mb/810.htm

It does say dont stick a k6-2 in it in the cpu info. 🤣.

Kinda sucks since the cpu is so fast.

emosun wrote:

http://www.uktsupport.co.uk/pb/mb/810.htm

It does say dont stick a k6-2 in it in the cpu info. 🤣.

Kinda sucks since the cpu is so fast.

Well...looks like your VX board isn't K6-2 compatible.
Do you happen to have any other more recent s7 or ss7 boards laying around?

I would risk it. The k6-2 is very common and not expensive. Just use a good p3 cooler and you're good to go.

The intels required 2.8v and ran fine on the older boards with only 3,3v support. they also just needed a bit better cooling to stay safe.

I have to agree, k6-2 is super common and cheap, I have like 4 or 5 and I don't have to many CPUs and nothing rare.
also 2.2 to 2.8v is what a 30% increase? certainly high but nothing absurd, I think if you give it a lot more cooling than it would get originally, and also if you cool the motherboard, the voltage area... I would think it will work ok.

Wouldn't there be any kind of risk to any of the other components if a CPU fries? I'm not entirely sure the motherboard will like it.

But it's true that K6-2 is very common indeed, but in the end it's up to emosun. Though personally I wouldn't even bother to try.

Tetrium wrote:

Wouldn't there be any kind of risk to any of the other components if a CPU fries? I'm not entirely sure the motherboard will like it.

But it's true that K6-2 is very common indeed, but in the end it's up to emosun. Though personally I wouldn't even bother to try.

I agree. There's a high chance of killing not only the CPU, but the board as well. Eh - in the end it's your hardware, do whatever you want with it.