Form Factor: Micro-ATX: 24.4 cm (9.6 inches) x 24.4 cm (9.6 inches)
Chipset: GeForce 7100/nForce 630i
Front-side bus speed: 800/1066/1333 MHz (processor dependent)
Processor upgrade information Socket type: 775
Motherboard supports the following processor upgrades
• Intel Core 2 Duo (Wolfsdale) E8xxx
• Core 2 Duo E6xxx (Conroe) up to E6850
• Pentium E2xxx series (Conroe) with Dual Core technology up to E2160
• Core 2 Duo E4xxx (Conroe)
• Celeron 4xx series (Conroe) up to Celeron 450
The Compaq Presario CQ3080IX Desktop PC uses the MCP73M01H1 (Napa) motherboard and it was sold with an Intel Core 2 Quad Q8200 installed. HP shipped a few PC's with that motherboard with faster quad cores up to the Q9400. You just need to make sure that your BIOS version supports the CPU you want to use before you change the CPU.
Read sumsolstice's reply on the HP Support Forums here:
Thankfully this kind of stuff should basically go away with the new best answer system. Mousemonkey went through and closed a whole bunch of my old threads about a year ago and that helped but they still pop up on occasion.