GOOD NEWS AND BAD NEWS

Good:
THE QX9650 WORKS WITH THE P5WDH. I'm using it right now at stock. I have no time to mess around with overclocking. Voltage control works (bumped it up to 1.4v, will lower it later). Using 2403 BIOS. Also there is FULL multiplier control apparently (not tested), so I suspect the MP issue is also fixed with the older chips, where it got broken with 1602+

Bad news:
ATTN: Larywild:
THIS CHIP DOES NOT WORK with your modified BIOS! And I suspect many other 45nm chips also will not work. With your BIOS, it detected a 600 mhz CPU, said ucode error, and any attempt to save any settings in the BIOS and exit, caused the computer to not POST ever again, until a CMOS reset.

I was able to download the 2403 BIOS and flash that (somehow the Ez flash utility still worked right after a CMOS reset) and it STILL didn't post, but after I cleared CMOS AFTER the flash: Presto=)