I said I'd try and help my GF's parents with their desktop. The only problem is how fast it loads programs. About the machine 1)It is a couple years old. 2)It is a Dimension 4550 series computer 3)It is a 2.0 GHZ P4 4) its recently been reformatted with a clean install of windows XP home (within 6-9 months) 5) Currently its RAM 256 MB DDR SDRAM 233 Mhz 128 MB AGP Aperture (from bios settings) 6) Disk is routinely defragged, Anti-virus scanned, ad-aware and spybot scanned. 7) With no virtual memory the computer cannot load all programs at start up (it loads most but when norton system works goes to load show in the area I get an error message saying there is not enough memory and with CRTL+ALT+DEL and performance the bar is mostly green and up to 233. 8) The virtual memory has been set to 1024 (MB starting) and max of 2048 9) The PC is used mostly for Email and word (even these take forever to load) Now for the questions. 1) Given what I mentioned that its 233 of 256 committed without Norton loaded (would be over 256 at and the computer is a 2.0 ghz and is used mostly for browsing and word processing along with AIM from time to time when their kids are home and other odds and ends DVD maybe a burnt CD and or music (so a simple use computer) how much RAM would you suggest, I personally would to 1 GB but they won't use the computer like I would. So 512 or 768 or 1024? 2) Is there a loss of performance if I were to choose to mix sizes of Sticks of RAM? ( 256 and 512 for example)? 3) Is dell a company and the requires certain brands RAM to actually work or will any old brand work? 4) If it comes you having say 1 GB of RAM in the machine is 2x512 or 1x1024 the better choice? (I've always been told 2x512 is better than 1x1028 because data from RAM can be recovered quicker? Thanks for your input guys, I've built my own systems before, but if I did something less than perfect i was the one that had to live with it and I always did the 2x sticks of ram of the same size. But this is the first time I will try and upgrade an OEM computer.