In todays world, any electronic component, or device, is utterly obsolete at around 3 years of age.
Current CPU's use 1150 style socket, which made the previous 1155 style socket obsolete last year.
I built a new desktop computer from scratch in Aug 2012 using an Intel i7-3770 CPU with 1155 socket - and it is already obsolete.
The P4's use a 775 socket which became obsolete about 2009.
I have a nice used Gigabyte motherboard and Intel P4 3.00Ghz CPU for sale, from a previous upgrade, and I can't even get a kind look for it.