Genuine Dell TP406 Motherboard For XPS 420, Supports The Following Processors: Intel Core 2 Q6600 Quad Core, Intel Core 2 Duo Processor E8400, Intel Core 2 Q8200 Quad-Core, Intel Core 2 Q9400 Quad-Core Dell Compatible Part Numbers: TP406 Genuine Dell TP406 Motherboard For XPS 420 Supports The Following Processors: Intel Core 2 Q6600 Quad Core Intel Core 2 Duo Processor E8400, Intel Core 2 Q8200 Quad-Core, Intel Core 2 Q9400 Quad-Core Dell Compatible Part Numbers: TP406