MOBO SWAP XPS TO OPTIPLEX

hi community,

 i have an old xps 400/9150 pentium d 960/ p945 chipset. im thinking of swapping out to another board to get around the chipset that is holding me back too 4gb of ram; and moving up to windows 7 64bit.

 I found an optiplex Gx745 sff mobo with Q965 chipset. i looks like it will mount right in my xps 400 chassis. has anyone done this before so i know what headaches im looking at. im thinkin i should be able too download the chipset driver and not sure which bios i would need yet. does anyone have any input on this that would help???

 Or maybe i should just grab a xps 420 board that i found with the x38 chipset and get different processor???does anyone have a better idea to build up with what i have? please help ??? thanks