The 4400 uses a Northwood processor with a 400-MHz FSB and 512K cache, while the 3000 uses a Prescott with an 800-MHz FSB and 1G cache. They are not interchangeable. It would probably be cheaper to buy a newer used system than upgrade the processor in the 4400.
Hello all, recently i acquired a Dell Dimension 4400 and liked the fact that it had an AGP slot opposed to the Dell Dimension 3000 that i already had but the 4400 has a slower processor. so i figured i would just swap it with the one from the 3000, so looked up the specs and they are the same socket type and it also said that i could only have a max of a gig of ram. so one day i got curious and put the 2gigs of ram from my 3000 in the 4400 and booted it. to my surpise bios and XP registered two gigs of ram which was of course more than Dell tech specs said it could handle so i figured what the heck so i swapped the proccessors and when i booted the 4400 and the 3000 with the switched processors neither of them booted and both of them gave me a solid amber power light and the error LEDs did not light and i did not get a video on the screen. when i switched the processors back to the right computers they booted just fine with no problems. so what i wanted to know is of there is something special i was supposed to do aside from just switching the processors and booting.(such as change a jumper or something else)(oh and if this helps i checked the manual and the s\n on the 4400 board and it is in fact the 4400 board) im open to any help yall can give

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic