Non plus cpus are pretty much already at their max. So usually even small overclock is not possible. Even some plus versions have trouble working at 600Mhz.

The K6-2 550 is indeed already at the max. Perhaps you could dive into optimising BIOS settings and improve RAM latency settings. The difference between poor and optimal RAM settings might be, in some cases, bigger than 50MHz extra CPU clock 😀.

Are you all smoking something? Have you actually ever tried overclocking a regular K6-2 on a good board?

Back in the day, when I had a K6-2 550 on an ASUS P5a as my main \ only machine, I had it over clocked to 660Mhz (120*5.5) on air.

Saying the 550 and even lower regular K6-2 CPUs are at their max is silly.

CXT CPUs commonly have another 50mhz in at least, the sticking point for pre-CXT was around 366-400, so if you had a pre-CXT 350, you may have been "at max" practically. There were meant to be some highly cherry picked 400s, but few and far between, very small yield.

So anyway, check 2x works on a lower FSB, check RAM/Cache timings backed off, check revision oddities of chipset (Early ALI Super 7 had some sticking point I think) Check you are getting voltage at CPU you're supposed to, if it's only getting 2.1 V or something it will hold it back. Also you might be getting volt droop at a higher clock, so maybe giving it 2.5 will help.

I ran a 500AFX at 570MHz for years, I think at 2.4v. I've seen 550AGR at 600MHz, at 2.5v iirc. I think some of the 533AFX will hit 600MHz. You can try and see what you get. Watch the temperatures on the CPU and VRM components.

If you search on this forum, there are probably lots of posts about overclocking the various K6 chips. If 600 is your goal, the "plus" chips are probably the easiest route. Good luck!

The K6-2 533 I had was possibly the worst overclocking CPU I've ever had. IIRC it was the 2.4 volt model and I had to boost the voltage to get 550 MHz out of it. The lower the core voltage the CPU is rated for, the better your luck will generally be for overclocking it.

kixs wrote on 2026-09-07, 09:03:

Non plus cpus are pretty much already at their max. So usually even small overclock is not possible.

This has been almost my experience. I've had a 475MHz K6-2, which ran stable at 500MHz, but any higher than that and it would crap out during POST or early DOS boot.

kixs wrote on 2026-09-07, 09:03:

Non plus cpus are pretty much already at their max. So usually even small overclock is not possible. Even some plus versions have trouble working at 600Mhz.

Can confirm, I have a K6-2+/550ACZ that is rock solid at 550 but unstable at 600 even with increased voltage. It will POST but starts getting geomety errors in OpenGL games and freezes after 20 minutes.

I haven’t had time to explore this more but my attempt to simply set the multiplier to 2x resulted in no POST. So not yet at the point of even being able to experience instability.

It was some time ago but I believe I tested this processor in a P5A-B at 600Mhz and it worked fine.

I don’t know if the BIOS on the Chaintech lacks support or the voltage needs to be increased or what the case might be. Hence the post here to see if anyone else has the same board (Chaintech 5AGM2) and has tested a non-plus K6-2 at 600. Maybe it’s just a disappointing budget board.

I've never used a K6-2-550, although I have one that I keep aside, in case I need it in the future, and I have various K6, from the first K6 to the K6+, I recently performed some tests on a PCCHIPS with AMD K6-2-380, I overclocked at 400 MHz, and it worked without any problem, later I tried a higher frequency, but with lower FSB, the result of the benches was better at 400 MHz, so it seems clear, that to get better performance, just go up with the FSB, and even if you are just below 550 or just above, you will see a certain improvement (from the benches), it is not said that it is possible to see it at eye.
I attach a table, of overclocking with K6-2, I think they are all CXT, but I remember that the multi 6X (2X), in the previous ones does not work, that is, they only go to 2X.

cyclone3d wrote on 2026-09-07, 13:57:

Are you all smoking something? Have you actually ever tried overclocking a regular K6-2 on a good board?

Back in the day, when I had a K6-2 550 on an ASUS P5a as my main \ only machine, I had it over clocked to 660Mhz (120*5.5) on air.

Saying the 550 and even lower regular K6-2 CPUs are at their max is silly.

I usually could only get about 50-75mhz of overclock on the old K6-2’s and even less before chompers and 2.4 volt versions.

It’s all hit and miss , if you have a bunch of 550’s you will find a fair amount of variation and need decent heatsync and fan to start.

Repo Man11 wrote on 2026-09-07, 18:11:

The K6-2 533 I had was possibly the worst overclocking CPU I've ever had. IIRC it was the 2.4 volt model and I had to boost the voltage to get 550 MHz out of it. The lower the core voltage the CPU is rated for, the better your luck will generally be for overclocking it.

+100%

I had zero luck with 2.4 volt k6-2’s
I never knew they made anything faster than 450 in the 2.4 volt version until years later

During that time AMD got 1 cpu that could run faster than 500mhz out of 88 k6-2 dies.

The k6-2 533 was an oddity much like the 433, I never owned a motherboard with the strange FSB they used so no idea how or what they worked on correctly

cyclone3d wrote on 2026-09-07, 13:57:

Are you all smoking something? Have you actually ever tried overclocking a regular K6-2 on a good board?

Back in the day, when I had a K6-2 550 on an ASUS P5a as my main \ only machine, I had it over clocked to 660Mhz (120*5.5) on air.

Saying the 550 and even lower regular K6-2 CPUs are at their max is silly.

I smoked a K6-2 500 once; unfiltered and mild. Harmful yet not addictive 😉. I don’t remember the specs exactly but I used ice-water cooling and wanted it to at least boot at 600 which it didn’t. I increased the voltages step-by-step until it blew. It was a very poor overclocker and such CPU is considered, to me at least, to be at its max. Sure it could go a bit past 500 and maybe 50MHz over but that would already be pushing it 😀.

I think your 660 is one of the better ones 😀.

byte_76 wrote on Yesterday, 07:44:

I don’t know if the BIOS on the Chaintech lacks support or the voltage needs to be increased or...

If it works at 550, then the BIOS is fine. What is the voltage now?

I was curious, so last night I tried a standard 500AFX and got it working at 600MHz with 2.3v. I also tried a few 400ATZ (T=1.6v) plus CPUs. At 2v, 2 out of 3 chips would do 600MHz, and one 570. I can't go any higher with the board I have out on the bench. Stable clock speeds are affected by things like temperature, voltage, and the silicon lottery.