Asus P4T533-C 3.4GHz works, 3.45GHz doesn't

[ssassen]

Okay, thought I'd run this by the die-hard OC-ers here as me and JC couldn't figure this one out, here the config and the problem:

- Asus P4T533C
- 2 x P4 3.06GHz HT Engineering Samples
- 2 x 256MB PC1066-32ns, Samsung RDRAM
- ATi Radeon 9700 Pro, does 380 core/345 mem
- Promise TX2000 RAID controller
- 2 x WDC 800JB, 80GB, 7200-rpm, 8MB
- Antec PP412X 400-watts PS
- Creative Labs Audigy2
- Windows XP Pro, SP1, latest updates

Got two 3.06GHz P4s here, both run fine with air-cooling at 148/37 FSB/PCI default Vcore, which yields 3.4GHz. I can run at this speed with the case closed for hours on end and it keeps on running whatever I do.

However when I up the FSB to 150/38, which yields 3.45GHz it crashes in a few minutes, even when I up the Vcore to 1.6, 1.7, 1.75, 1.8 or 1.85. Mind you this is only 50MHz more on the CPU.

But here's where it gets strange, when I clock the PCI down to 150/30 you'd think it'll work if it were a PCI issue as the PCI-bus is now underclocked, well, it doesn't, same problem. If I set the memory back to 3x, yielding 900MHz for the PC1066 RDRAM, it also crashes.

So what is wrong with this picture? This would be the first CPU that wouldn't do 50MHz more even with 20% extra Vcore that I ever came across, but wait, what makes it even more spooky is that I have two CPUs that have the exact same behaviour, something tells me the P4T533C is acting up.

Anybody got a P4T533C and have similar probs?

Have a good weekend,

Sander Sassen

Email: ssassen@hardwareanalysis.com
Visit us at: http://www.hardwareanalysis.com

[markodude]

Have same prob with my 2.50 C1 stepping, will do 2.8 (112FSB) no problem (prime stable), at default voltage. I can add 5, 10 or 15% more voltage but it wont go any higher prime stable.....
I think cooling is the prob though, my temps hit around 50degrees under full load (thats with a huge hole in the case and a few case fans...) - prometia might help!

[Hamburger]

Ummm, please pass me one of those ES . lol

I sure hope its the board and not the ceiling of those 3.06 HTs.

[phantom punisher]

im experiencing around the same results with my chip perhaps this is the top speed for this stepping.

[jdmcnudgent]

what bios are you using?? the 1.03 seems to be the best, from bignuttz experiences, as he has 2 of those boards. one he can run pc800 in 4x mode, no problems, but, if he switches the bios, he cant even run the pc800 at 133.:( i would try to flash the bios first.;)