Despite what is on Intel’s website, the Intel DG33TL does not support Core 2 Quad Q9550 CPUs and has trouble with 1333 MHz FSB chips in general. I also ran into problems with Core 2 Quad Q6600 chips, but not on every board.
Most of the time, the board will post and will work somewhat, but things like virtualization support in the BIOS won’t show up. Other times, the board will not post and doesn’t seem to work.
This board also seems to be very picky about RAM. If you put some RAM in the first and third slots, it won’t post, but if you put it in the second and fourth slots (and put a different brand/model RAM in the first and third slots), it will post.
I’d steer clear of this board unless you are looking to use it with a 1066 MHz or less FSB CPU with either single core or dual cores.