RAM or CPU problem?

[potatobbq]

I have P3-933 w/ Alpha PAL6035 heatsink and 256Mb of PNY PC133 and it seems to runs fairly stable at 1050MHz@1.8V (150MHz FSB) on my ASUS CUSL2-C but after a while, I get errors in Prime95. The CPU temp is around 35C idle and reaches 45C max running Prime95. Is there any way to tell if it's the CPU or the RAM that can't handle the higher speeds? I looked the stick of RAM and there's no brand name or anything on the chips so I don't know who really makes the chips, all I know is that it's assembled by PNY...

[DocClock aka MadClocker]

That is a lot of heat there...my overclocked PIII gets a little weird at above 37c....I am surprised that you have so much heat, when u are using an alpha...did you use thermal compound? did you use the stuff that came with the h.s.? if so, try Arctic Silver thermal compound..it made a 4-7c drop in my temps, but your cpu should be idling at around 26-30c at idle, and shouldn't go above 37c if you want stability..(imho)
You might need to lap the heatsink, but I wouldn't lap the cpu..that is only for people with money to burn.
Can you try to reseat the heatsink...one other possibility, is you might have too much thermal compound...too much in this case is worse than not enough...you could also try to cool the clock generator as well.
these suggestions should at least wake you up to a couple of possibilities...hope they help

[batboy]

Sounds like you need to bump the voltage up to 1.85 to be stable, but with temps hovering around 45 degrees, you're very borderline on overheating.

That Alpha PAL should be doing a better job than that, those are normally excellent coolers. Is the heatsink sitting nice and square on the CPU?

You are using a good thermal paste right? Maybe you need better case cooling now. I've had good luck lapping the heatsinks.

Sometimes generic RAM can hold you back. Can you borrow a buddy's stick of good PC133 long enough to test? Memory prices are pretty low right now, if you do decide to buy. Good luck!

[DocClock aka MadClocker]

I forgot to suggest to run it with the case cover off, it helped me to reach my current speed, and until I can get to the rotozip and cut my case for a fan, it will stay open...if I close the case right now, in twenty min or so I will either have to reboot, and turn it down, or open the case.
Like Batboy said, it could be voltage, but I wouldn't even go there till you figure out your heat prob..the alpha should be doing a better job than that.

[potatobbq]

Hmm... I didn't think Arctic Silver would make such a difference... Right now I'm just using some Radio Shack heatsink paste so maybe it would help if I got some Arctic Silver. Thanks for all the help, I guess I'll mess around with the heatsink to see if that's the problem.

[batboy]

Some folks report better results with Arctic Silver than others. Personally, I only saw about 1 degree decrease in temp under load, but I was already using a good thermal paste and had the heatsink lapped. Others have reported much greater drops in temps. I guess, your mileage may vary.

[potatobbq]

I went ahead and ordered some Arctic Silver so hopefully that will help a little... but I guess my question is still... is there a way to tell if it's the RAM or the CPU that can't handle the higher speeds? I don't really want to bother buying new PC150 memory if it's my cpu that can't handle 150MHz fsb anyway.

[DocClock aka MadClocker]

Well, that's a toughy...you see overclocking is more of an art than science..and what works for one may not work for others, but in answering your question, there is no real way to know, except by experience...sometimes certain problems might point you in one direction or another...one way is to maybe borrow a stick from somebody...the PNY mem that I bought is infineon...I can't remember what the chips were, but it ran good at 140mhz cas2...I can't remember where it toped out, but I went to Mushkin rev2 pc133, and never looked back...and haven't been at 140fsb in a long time. BTW both Mush'n and it's compeditor are at very low prices right now.

[batboy]

I'd first deal with the cooling issues, then maybe bump the voltage up one more notch. Maybe tweak the RAM timing in the BIOS a little, sometimes that helps. If it still won't go, borrow some better RAM and try that. If you have more than one stick, try taking one out. I've heard that works sometimes. Try everything, that's what overclocking is about.