I was looking to upgrade my E6400 to a Q9400 Quad core on my HP m7690n is that possible? I bought the CPU it matches the Socket 775 board of 1066 max ghz. Sorry I am new so I was wondering do I have to do any tweaks? Any comments appreciated...!!!
You will not be able to use the Q9400 with that motherboard. Yes its the same socket but your motherboard only supports up to 1066mhz FSB the Q9400 is 1333mhz. You will have to get a new motherboard that will support that processor, but by doing that your copy of windows will not be able to validate and you will need a fresh copy of windows. There is absolutely nothing that can be done to make that CPU work on that motherboard it has an old chipset and simply can not support that processor.
The fastest that will work for sure is an E6700 @ 2.66GHZ which will not add much of a performance gain. Your motherboard like I said before has an old chipset Intel P965 which does not support anything over 1066mhz FSB and from the spec sheet it will not support quad core and 45nm processors. Your only real option is to upgrade the motherboard.