can I upgrade my pentium d on my gx280 lga775 to core2 duo

Depends on your motherboard. You need to see what processors your motherboard supports.
 
Early 775 boards only supported P4/PD and not C2D, so as voyager has been stating it depends entirely on the board itself.
 
I just realized he's posting about an Optiplex GX280. The answer is no. If you want a core 2 duo you're going to need to buy an Optiplex 755 or newer.
 
The 945 chipset will only run a few of the older core 2 duo's. You would need the 965 chipset to run all of the core 2 duo's.
 
Back
Top