P4 1.6a won't clock as high anymore, what did I do to it? Fixed I think...

[Freejack2]

I have a p4 1.6a in an Asus p4b533 with 512mb (2 sticks) of crucial pc2100 ddr.
I had the system stable at 2512 (157fsb x 16, pci 33, agp 66, memory 4:3 ratio 118/236ddr, 1.675 volts) passing 28 hours of prime95 earlier.
Then I took my cpu out and put it in my wifes p4b266-c and put her cpu in my computer so I could test her cpu to see what it's max was.
That went fine, but when I went to put my cpu back in my system, now all of sudden I can't clock it very high, it within a few minutes at 2512 reboots or blue screens.
I wondered if the ram was failing so I dropped the cpu to 2133 (133x16, 1:1 ratio 266ddr 1.55v) to push the memory and no reboots.
I then took off the stock heatsink and put the Volcano 478 I also got with this cpu. I took off the stock pad it came with and rubbed artic silver into it, cleaned the cpu off with 91% isopropyl alcohol and put a fresh coat of arctic silver on it, even cleaned the artic silver out of the hole.
Though, even with the stock heatsink, at max speed the cpu never got over 57c. Now with the Volcano 478 it's 32c right now under a prime95 load. So I'm pretty sure this isn't heat related.
I tried changing it to 2399 (150x16 4:3 ratio 224ddr 1.65v and 1.675v) and it goes for a couple of hours before rebooting or blue screening.
I switched it to 2192mhz (137x16 4:3 ratio 206ddr 1.55v) and it's been stable even with prime 95 running for the past 3 hours.

One other thing of note was I got a stick of 512ddr ram that was defective that I had tried in my system with my crucial ram. Once I determined it was bad I took it out and just kept my crucial ram in. Problem is I can't remember if I did this just before I took out my wife's processor and put mine back in, or just after that.

What of these things that I've done could have caused the cpu to all of a sudden stop overclocking so high?
If you have any questions please free to ask. Thanks.

Edit: Almost forgot. I also updated the bios from 1007 to 1008 sometime after putting the Volcano 478 on. Didn't help at all but didn't seem to hurt anything either I suppose.
Power Supply is an Antec Truepower 550, vid card is an oem ati radeon. Asus Ti4600 shows up tomorrow. Any other specs are under my system rigs under cow.

 

[Duvie]

That 1.675v is set in bios right??? That means by the time you figure in asus overvolting you may have 1.755v actual....That is a bit high IMO....

The signs of damaging the cpu could look like that, but so could ram...

 

[LastRide]

With it at idle you would get 1.735V in that area with 1.675V applied in bios.With 3:4 hack enabled you be looking at an extra .01-.02V so you would be at 1.745-1.755V around there.Under load your V would be around actual voltage applied.I won't go over 1.65V with my P4B533 which gives me about 1.71V at idle.I actualy run mine at 1.55V at 2.2GHZ to be safe.My 1.6a won't get big numbers like some others.Duvie's right though,thats a sign of your CPU being damaged.All you can do is try another stick of ram and if that don't help its your CPU.

 

[Freejack2]

Well this has been pretty interesting. I didn't think this would make any difference with an Antec Truepower 550watter but apparently plugging in both secondary power connectors on the board seems to have helped.
I had read about it somewhere for the p4b266-c and tried it on a whim. 36hours no reboots or blue screens. 2512mhz@1.65 volts
However the one odd thing was prime95 itself crashed about 12 hours into testing, though at the time I had a zillion windows open doing tech support and it happened just as I opened a new pcanywhere window.
Since then it's been perfectly stable, passed 27 hours of prime95 without a hitch.

Is it possible that the Antec truepower series doesn't pass enough juice on that 12v extra connection but will if you plug it in twice?

 

[sticky52]

I had the opposite problem with my Abit BD7. Popped my 1.6A out to see how a 1.8 would overclock. Not by much apparently so back in goes the 1.6A. Previously, I only made it to 133Mhz FSB, but now I have it running Prime95 for days at 166Mhz FSB. Go figure.