can a K6 take 0.7 volts extra?

Discussion relating to Socket 7 hardware.
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jeepster
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can a K6 take 0.7 volts extra?

Post by jeepster »

I bought a VA-503+ mainboard, as I heard they were pretty good
(even though AT not ATX). It included a K6-2+ 500 MHz. The seller
claimed that it was stable at 616 MHz with PC133 RAM, and a larger cooler
(for Duron/Semprons).
When I got it, I found it was jumpered to 5.5 x 112, but also to 2.9 V,
when the CPU is only 2.2 V.
This seems like way too much. I never cranked up a K6 by more than
0.4 Volts before.
How long will this last?
:?:
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jsc1973
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Post by jsc1973 »

If that CPU is really a K6-2+, then it won't be rated at more then 2.0v stock. What you have is likely an ordinary K6-2 500 CPU of a later stepping, which were rated at 2.2v.

Even for a 2.2v CPU, running at 2.9v is a big risk. You will definitely reduce the life of that processor, operating that far out of spec. But there's no telling when it will fail.

If you lower the voltage, the CPU likely won't run at 616 anymore. Most K6-2 (but not K6-2+, which was made on a .18 process) processors have issues going over 500 anyway; AMD's own K6-2 550 was a factory overclock that caused a lot of problems. The one you got only made it to 616 because of the massive overvoltage.

Given the easy availability of K6-class processors today, I wouldn't worry about it. If the CPU fries, get another one for $10 on ebay.
FIC VA-503+, Rev. 1.2, AMD K6-III+ 450@550MHz, 80GB Seagate ATA-100, 3dfx Voodoo3 3500 TV, TB Montego II Quadzilla, Win98se, 384MB PC100

Compaq Presario 1273, AMD K6-III+ 450@400MHz 1.8v, 40GB Samsung 5400RPM, extremely hacked Win98SE, 288 (yes, 288!) MB RAM
(Also an AMD FX-8350, which does the heavy lifting these days...)
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Post by Jim »

Personally, I would pull the heatsink off of it and eyeball the cpu and its rated voltage. Most K6-+ processors will hit 616 MHz at much lower voltage than that. 2.1v - 2.3v at most. If it turns out to be a plain K6-2 with no + then either downvolt it to about 2.4, and accept the resultant loss of speed, or replace it with a K6-+ processor. The reason for this being that there is a good chance that you won't just fry the processor if you leave it running at 2.9v; chances are the thing will get so hot that you'll fry the mobo too. (Melt parts of the processor socket.)
Last edited by Jim on Fri Oct 15, 2010 5:52 pm, edited 2 times in total.
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jsc1973
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Post by jsc1973 »

I've never heard of a processor socket melting unless the CPU fan failed, and even then, never on a K6-2.

I wouldn't think a CPU running at 2.9v on a .25 micron process could get that hot with any kind of decent cooling. AMD once made a K6 processor that ran at 3.2v on a .35 process, the K6-233. It ran as hot as a P4 Prescott, burnt out the capacitors on cheap motherboards, but I never heard of one melting anything.

I can, however, second the idea of replacing that CPU, whatever it may be, with a nice, cool-running K6-2+ or K6-III+ processor that will run at 2.0v, or no more than 2.2v overclocked. At 616 MHz, one of those will run like a K6-2 at 900--if you could somehow get one to do that.
FIC VA-503+, Rev. 1.2, AMD K6-III+ 450@550MHz, 80GB Seagate ATA-100, 3dfx Voodoo3 3500 TV, TB Montego II Quadzilla, Win98se, 384MB PC100

Compaq Presario 1273, AMD K6-III+ 450@400MHz 1.8v, 40GB Samsung 5400RPM, extremely hacked Win98SE, 288 (yes, 288!) MB RAM
(Also an AMD FX-8350, which does the heavy lifting these days...)
1BadMoJoe
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800MHz is the current highest clock for an AMD K6 CPU

Post by 1BadMoJoe »

690MHz has been done on an K62+ 500 so 612MHz may be done with yours only without the stock heatsink. For stability an aftermarket heatsink is required or with water cooling.
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RE: 800MHz is the current highest clock for an AMD K6 CPU

Post by Jim »

There was one guy who used phase change cooling to go over 700 MHz. There is a post about it here somewhere.
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jsc1973
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Post by jsc1973 »

The biggest overclock I ever heard of with one of these chips was 744 MHz, using the 124 MHz bus speed and a multiplier of 6 on an FIC VA-503+. They had to pull the cover off the K6-III+ and put the heatsink directly on the CPU core, ala the Athlon XP. I think it also involved the use of watercooling.

The theoretical top speed for a K6 would be 800 MHz (6*133), attainable on an ALi Aladdin 7 board that officially supported a 133 bus speed. But even if you pulled it off, you'd be running without the L3 cache, which wasn't supported on Aladdin 7. I think the 744 MHz with the L3 would be the fastest possible Super-7 configuration.

AMD had the capability to make K6-III chips in the 600-700 MHz range in the 2000-01 timeframe, but decided against it when their yields (and demand for) on the Athlon and Duron were outstanding. It was a good business decision, but I would have liked to have a faster K6-III.
FIC VA-503+, Rev. 1.2, AMD K6-III+ 450@550MHz, 80GB Seagate ATA-100, 3dfx Voodoo3 3500 TV, TB Montego II Quadzilla, Win98se, 384MB PC100

Compaq Presario 1273, AMD K6-III+ 450@400MHz 1.8v, 40GB Samsung 5400RPM, extremely hacked Win98SE, 288 (yes, 288!) MB RAM
(Also an AMD FX-8350, which does the heavy lifting these days...)
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Post by Jim »

http://www.k6plus.com/index.php?name=PN ... pic&t=1909

His name was Turrican. Unfortunately most of his photos seem to have died since it was originally posted.
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2x256 Meg PC 133 Hynix SDRAM
1x 20G Maxtor (7200)
2x 80G Maxtor (7200) Ducted w/ 2x486 Fans Mount
52/24/52/16 LG CDR/RW/DVD
8/4/3/12/24/16/32 LG Super Multi
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tazwegion
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Post by tazwegion »

Jim wrote:http://www.k6plus.com/index.php?name=PN ... pic&t=1909

His name was Turrican. Unfortunately most of his photos seem to have died since it was originally posted.

Actually it seems he spurned on at least one other to use such extreme cooling solutions on a SS7, massman also a member over at xtremesystems.org had a crack at pushing the envelope of the K62-500 posting at 720Mhz (back in 2007) you can read the thread HERE (with pics) :twisted:


As for running an additional 0.7v I'd highly recommend you DON'T... I killed the odd K62 over-volting to a mere 2.5v :cry:
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