Someone else has tried this with some success.
In case anyone is interested or searched in future, I upgraded my P4 630 to a PD 945 without any problem. Even clearing CMOS was not necessary (I disabled HT before removing the old cpu though). One thing to mention is that after reading a few posts on various steppings and compatibility issues, I looked for an e-tailer who guaranteed to ship a newer stepping PD 945 cpu (SL9QQ instead of the older and widely available SL9QB). You might want to look for the latest stepping cpu as well.
Also, I bought my Dimension in July 2005 and the motherboard model is 0X8582.
The Intel PD 945 is the 3.4 Ghz 800fsb processor.
I do not think your MB supports Core2 duo's.
Edited by SRX660, 07 February 2008 - 07:57 PM.