Looking to OC a K6-3/450

[Psycho-holic Slag]

I've got a K6-3 450 (the 2.2 V model) and an ASUS P5A-B mobo, which I'd like to OC just a little. from what I understand, there's two ways to do it: I can either up the bus speed which would go from 100 to 105, or I can bump up the multiplier. I'm guessing that if I up the bus speed since everything else goes with it (PCI/ISA/memory, etc.) that I'll get more of a boost across the board, but increase my liklihood of screwing up other hardware. I'm also guessing if I up the multiplier (from 4.5 to 5) I'll get a better CPU boost, with less risk to other components. does that sound about right? anyone have any advice for an unexperienced overclocker? i can't afford to blow my processor, but I think I'm safe with a minor overclock to 500. not sure about the voltage, though. my actual is 2.24V.

as far as cooling goes, beyond the standard I'm using ArcticSilverII thermal grease, a case fan which runs at 4800 RPM, a PCI slot fan, rounded cables, and when I'm not gaming I run Rain (software cooler). I think Rain will serve well to prevent my CPU from 'premature' aging while my wife uses it during the day for internet ****.

Thoughts? advice? Thnx in advance.

[eagle1]

Yeah.. if you want to be on the safe side, you could just take your multiplier setting up a notch.. but definitely the fsb OC is better.. It gives you more speed..!

[RADAR1797]

The old K6-3s are not great overclockers. Unlike the K6-2 with no L2 cache, the K6-3 sees more gain from raw CPU MHz increases. If you can get 500 MHz out of it and do not have to raise the voltage over 2.4v, you will see the best performance boost. I would not worry about 5 MHz increase to the FSB, it will do no harm to your components.

-RADAR

[This message has been edited by RADAR1797 (edited 08-05-2001).]

[Psycho-holic Slag]

Well, here's the chart on CPU to BUS frequency multiplier:

CPU -> 100 105 110 etc. (mhz)
AGP -> 66.6 70 73 etc.
PCI - > 33.3 35 36.6 etc.

so if I up the Bus multiplier to 105 I'll be running at 473 mhz, as oppposed to upping the CPU external multiplier which would give me 500. of course I could go the 110 and get 495 mhz on the CPU... but at what risk to my other components? my memory is PC100, my voodoo 3 2000 is overclocked from 143 to 166 with a 486 fan glued to the heatsink (won't bother mentioning anything else). so the way I see it I have 3 options:

a) Bus frequency at 105 (CPU @ 473)
b) Bus frequency at 110 (CPU @ 495)
c) Bus freq. at 100, multiplier at 5 (CPU @ 500)

But as equally as important as knowing which of the above options is best (with safety in mind), is what voltage to set it at.

????

thanks again...

[RADAR1797]

5 X 100 MHz will give you the best performance with a K6-III. If you had a K6-2, I would go with 4.5 X 110, but your CPU has the internal L2 cache and that makes all the difference in the world. Keep the voltage to 2.4v or lower.

-RADAR

[Psycho-holic Slag]

thanks for the clarification... I thought that's what you were getting at. I will try 500mhz @ 2.3 volts first, and go from there.

Sincere thanks!

[wildbuffalo]

As RADAR1797 said, K6-3 450 with 256KB L2 cache at processor speed would be better at 5x100=500. That is if you can hold it stable at 500 at 2.4V. K6-3 are poor overclockers and tend to run very hot. If your cpu ain't stable at 500, chances are that's because its running hot. You would certainly need a very good Heatsink Fan on the cpu to keep it cool. I had a K6-3 350 which ran stable upto 400, and wouldn't do any thing above that. On the otherhand, with overclock using higher FSB the other peripherals are also overclocked. This may give you some more increase in overall performance of the system (hard drive and memory)

Wild

[Psycho-holic Slag]

temp is my biggest concern... as mentioned in my previous thread, my CPU temp is now lowered to 57 degrees Celcius after exiting 3d games. to get it to drop I have added ArcticSilver II thermal grease, a PCI slot fan, and rounded my cables in addition to the case fan I already have. the CPU heatsink and fan is a $20 job from Fry's.

I think I'm being conservative enough that problems with stability will surface before I fry anything. AMD doesn't give a max CPU temp in their manual... just a max case temp of 60 or 70 degrees celcius, which I am nowhere near.

[Psycho-holic Slag]

also, what makes a good over-the-counter filter for the case fan in front? i've got a 72mm fan that's pulling air through some tiny airholes in front... I'm thinking of drilling a 60mm hole, but would like to filter the dust a little. I'm trying to keep the expense to pocket change... would a Scotch pad do the trick?

[Psycho-holic Slag]

well, that was a miserable failure. at 2.2V, 2.3V, and 2.4V (@ 500mhz) the system wouldn't boot - blue screens, error loading explorer.exe, windows protection error, etc.

doesn't seem like 500 is going to work at all... I guess I'll try setting the BUS speed to 105, unless someone's got a better idea.

[xroyal]

I've got a III 400 2.2v which went to 450 (100x4.5 2.3v) easy, even 475 (2.6v) for a while before errors set in. Bottomline, I get best performance at 448 - 112x4. That's with Crucial CAS2/turbo settings on RAM. Did it w/PC100 fine, and now PC133. My last gasp will be to cool the Northbridge, and try 124FSB. Good luck.