Prescott LGA775 + 865PE... let's clock!

[Salkcin]

Hey

I recently recieved a Asus P5P800 using the "old" Intel 865PE for LGA775 Prescott's. I got a "520" (2.8GHz) and in some way I understand why Intel have a overclock limit under there 9xx chipset.

The CPU runs 250FSB at the moment (default voltage) 1:1 with a pair of Corsair PC4000 CAS3-4-4-8 and it's stable (260 or like proberly would to, but it's late now)
http://users.cybercity.dk/~dsl30381/p45201.jpg (see here - Enabling HyperPath gave 700MB/s - from 51xx to 58xx MB/s!)

At default voltage it boots at 280FSB (3,92GHz!), but not to Windows. Highest speed it boots to Windows at is 275FSB (3.85GHz), but it is'nt stable enough to complete SuperPi - I tried raising the vcore up to +100mV (1,5v), but it does'nt bring more stability in to the system.
http://users.cybercity.dk/~dsl30381/p45202.jpg (275FSB here)

unfortunately I got some memory issues. At 1:1 I can boot into Windows at 266FSB and complete SuperPi (37 seconds if anyone cares ), 5:4 does blue screen and random reboots and 3:2 will get it booting into Windows, but I suspect the memory is not happy running 3:2 like 5:4... even if it boots in to Windows.

I got a good watercooling setup - two 80mm fans blowing over mosfets and northbridge (heatsink on the mosfets is default ). The Powersupply is a cheap 550watt Q-tec Star VIP Gold (sounds good hehe)... maybe it's the hardware limiting me here since the CPU is using 122watt when loading at 275FSB and default voltage.

Another thing worth noting is the board does'nt recognize the CPU frequency above 3,6GHz - it's kind a random what speed it detects and in Windows CPU-Z is measureing a "unstable" FSB for some seconds (if it's set at 275MHz it will for example start measureing 266MHz for 1-2 seconds, then 272, 273 and finally 274,5...)

So.... now I wrote at roman, but check the potential of this mofo. It would might be worth trying the Abit AS8 instead wich also has the 865PE for LGA775