I would try reseating the CPU as well as replacing the heatsink compound.

Chances are, that after sitting so long, some of the pins have a poor connection in the socket.

an3k wrote:

after many many years I grabbed my ~1997 computer from the basement and started it. Beside the CMOS battery being empty (or dead - I don't hope so) everything works fine. However my K6-2-500 treats a 2.0x multiplicator as 4.5x instead of 6.0x. Additionally it treats 1.5x as 3.5x. 2.5x and 3.0 is treated as 2.5x and 3.0x. It's a Chomper-XT (26351 on base).

I suspect the dead CMOS battery might have something to do with it. I notice that according to https://www.asus.com/support/Download/1/5/4/1/8/ , the K6-2 ("model 8") was only supported by a later BIOS revision. Can you see any indication of what BIOS version your computer might be using? Maybe re-flashing the BIOS will do it. I assume this is the same CPU you used to have in there?

cyclone3d wrote:

Chances are, that after sitting so long, some of the pins have a poor connection in the socket.

That's a new one. Have you ever heard of that happening to a Socket 7 CPU before?

Your motherboard doesn't support a k62-500 cpu according to the review here http://www.tomshardware.com/reviews/motherboa … -review,10.html
and manual here http://www.tsukumo.co.jp/20thanniversary/comp … ASUS_manual.pdf

The cpu will work though, and what you have stated about the ratio's is correct as the motherboard natively supports 3x max, but the cpu internally
sees 2x as 4.5x. You will need a super socket 7 board for proper support. the only k6 cpus that can (not always) run at 600mhz are the k62+ and k63+ models.
You will probably get 337.5mhz by setting the fsb to 75 and ratio to 2 (4.5)

Imperious wrote:

Your motherboard doesn't support a k62-500 cpu according to the review here http://www.tomshardware.com/reviews/motherboa … -review,10.html
and manual here http://www.tsukumo.co.jp/20thanniversary/comp … ASUS_manual.pdf

The BIOS "version 0205" on the page I linked to specifically states "Add new AMD K6 support. (model 7,8,9)", which would be the K6-2 and K6-3. As that BIOS update was evidently released after the manual was written (and after that review), support for those CPUs would not be mentioned there.

Thanks everybody for your feedback!

I already reseated the CPU but that didn't helped. Before and after doing so the CPU had the same speed and there was no difference in system stability.

I use the latest BIOS version available 0206 so that shouldn't be an issue.

Maybe I just have party wrong information. Many years ago I printed an "overclock manual" for that board and it states that a K6-2+ (and a Chomper XT CPU) would use a 6.0x multiplier if a 2.0x multiplier is set. The german wikipedia also states that. However the english wikipedia says that only the K6-2+ does so.

Is the following true:
K6-2 interprets a multiplier of 2.0x as 4.5x
K6-2+ interprets a multiplier of 2.0x as 6.0x

If so then everything is fine and I just have the wrong CPU 😀 Good thing I found a K6-2+ 500 on eBay 😉

Regarding the CMOS Battery. The board doesn't have a typical CR2032 or anything else that looks like a battery. The manual says "Self-Powered Real Time Clock". Is the battery inside of that "chip" and is it somehow replaceable or will it charge itself when the PC is connected to power (but turned off)?

EDIT: The "overclocking manual" also provides information on how to set jumpers to provide voltages from 2.0 to 2.3 voltages (the P/I-P55T2P4 supports 2.4) additionally to those officially supported (2.5, 2.6, 2.7, 2.9 and 3.2)

Imperious wrote:

Your motherboard doesn't support a k62-500 cpu according to the review here http://www.tomshardware.com/reviews/motherboa … -rev […]
Show full quote

Your motherboard doesn't support a k62-500 cpu according to the review here http://www.tomshardware.com/reviews/motherboa … -review,10.html
and manual here http://www.tsukumo.co.jp/20thanniversary/comp … ASUS_manual.pdf

The cpu will work though, and what you have stated about the ratio's is correct as the motherboard natively supports 3x max, but the cpu internally
sees 2x as 4.5x. You will need a super socket 7 board for proper support. the only k6 cpus that can (not always) run at 600mhz are the k62+ and k63+ models.
You will probably get 337.5mhz by setting the fsb to 75 and ratio to 2 (4.5)

Back in the day I had a K6-2 550 running at 660 on an ASUS P5A. (5.5 x 120). I'm sure it supoported the 6x multiplier as well.

Looking up some stuff, it looks like all the CXT core (Stepping 8/[F:8]) based K6-2s supported the 6x multiplier.

Page 92 of the tech doc, available here states that.
http://www.amd-k6.com/cpu-specs/

Direct link to the tech doc.
http://www.amd-k6.com/wp-content/uploads/2012 … p_Datasheet.pdf

an3k wrote:

Thanks everybody for your feedback! […]
Show full quote

Thanks everybody for your feedback!

I already reseated the CPU but that didn't helped. Before and after doing so the CPU had the same speed and there was no difference in system stability.

I use the latest BIOS version available 0206 so that shouldn't be an issue.

Maybe I just have party wrong information. Many years ago I printed an "overclock manual" for that board and it states that a K6-2+ (and a Chomper XT CPU) would use a 6.0x multiplier if a 2.0x multiplier is set. The german wikipedia also states that. However the english wikipedia says that only the K6-2+ does so.

Is the following true:
K6-2 interprets a multiplier of 2.0x as 4.5x
K6-2+ interprets a multiplier of 2.0x as 6.0x

If so then everything is fine and I just have the wrong CPU 😀 Good thing I found a K6-2+ 500 on eBay 😉

Regarding the CMOS Battery. The board doesn't have a typical CR2032 or anything else that looks like a battery. The manual says "Self-Powered Real Time Clock". Is the battery inside of that "chip" and is it somehow replaceable or will it charge itself when the PC is connected to power (but turned off)?

EDIT: The "overclocking manual" also provides information on how to set jumpers to provide voltages from 2.0 to 2.3 voltages (the P/I-P55T2P4 supports 2.4) additionally to those officially supported (2.5, 2.6, 2.7, 2.9 and 3.2)

Looks like I'm wrong, the k62 data sheet says 2.0 ratio should be interpreted as 6x except older cpu revisions.
Maybe Your motherboard is over riding it and forcing 4.5x

Imperious wrote:

Looks like I'm wrong, the k62 data sheet says 2.0 ratio should be interpreted as 6x except older cpu revisions.
Maybe Your motherboard is over riding it and forcing 4.5x

Or it could be that the BIOS is not detecting the CPU speed properly.

I would suggest running something like CPU-Z to see what it says.

Or maybe a benchmark program to see if the reported speed matches the performance of the reported speed.

I think cyclone3d may be right.

Try the latest BIOS from here: http://web.inter.nl.net/hcc/J.Steunebrink/k6plus.htm
This BIOS will include K6-2+/III+ should you want to buy one in the future, but more importantly it "has also better support for the original K6-2CXT/III". Pretty sure this will fix your issue 😉.

If I do remember correctly, the first Chompers did not treat 2x as 6x, but this is definitely not your case, the K6-2 500 came out a while later.

F2bnp wrote:

If I do remember correctly, the first Chompers did not treat 2x as 6x, but this is definitely not your case, the K6-2 500 came out a while later.

Correct. Chompers did not but CXT (to the extent of my knowledge and testing) does.