upgrading by downgrading...

[wol-va-rine]

the kids' motherboard (Asrock 775DUAL VSTA) was crapping out so I bought "them" an ASUS P5W DH Deluxe, after reading up on it and the 975x chipset while waiting for it to arrive I decided to try it in my rig to see how far I could push my Q6600 (3.06ghz was as far as I could go with my P35 board)...

I now have the ASUS running at 3.15ghz, 1400 FSB without touching anything but the vcore (the vdroop on this board is...um..."interesting" to say the least, it fluctuates pretty wildly), once I get started doing some other voltage increases I may have to get another cooler, the Xigmatek S1283's little brother I have in this rig (S963) is struggling to hold on (mid 40s to 50°C at idle )...

the OC potential of this older chipset is pretty amazing, most reviews I've read of this board had it going 400mhz+, a 1600+ FSB for a stock 1066 FSB board, I may keep this in my rig, the P35 is running with an E6600 in the kids' computer right now and may just stay there, newer is definitely not always better...

 

[wol-va-rine]

the vdroop on this board is disheartening to say the least, I boot up in the bios at 1.4625v, cpu-z shows 1.44v and it drops to 1.384v-1.4v once I start running Prime95, I cannot get this board stable at 356MHz FSB, I'm running 351MHz right now, but that's with the vcore I just mentioned and the temps are idling in the high 40s, low 50s and reaches high 70s, low 80s during Prime95...

I've also pencil modded it to try to reduce the vdroop, but it doesn't decrease it much, just a little, even with the limitations and hassles, it has still overclocked my Q6600 more than my P35 Gigabyte board did...

 

[Atomic Rooster]

I was going to suggest maybe the PSU was rippling a bit and to try a different one. But the Antec PSU should have good voltage regulation.