I have a little dilemma. I currently use a Dell Optiplex 980 with a core i3 550 processor. Recently we got new computers, Optiplex 990. Their processor are core i3 2100. The 550 has 3.2ghz, 4mb cache and the 2100 is 3.1ghz and 3mb cache. Here's a comparison in case you need it: http://ark.intel.com/compare/48505,53422
Go for the Sandy Bridge (i3 2100) the new architecture is ~20% faster clock per clock and is faster at handling threads. also the HD Graphics 2000 IGP is vastly superior to the GMA HD on the old i3 550 (Clarkdale). just to remind that these CPUs are are using different sockets and are not compatible with each other's respective platforms
