BX80569Q9550A - Intel Core 2 Quad Q9550, Yorkfield Core, S775, 2.83GHz, 1333MHz, 12MB L2 Cache, 8.5x, 95W, Retail
Definitely a good upgrade option if you still keep the old core 2 motherboard and just updating the processor .
Not sure which stepping is this (C1 or E0?) The E0 stepping is slightly better but the C1 stepping is backward compatible with old motherboards especially the DELL XPS 720.
Also it is £174.74 from scan