Quote:
Crucial says I need 2.5v but Dell states 3.3v. Who's correct?


Are you certain that you didn't mis-read something on crucial.com? There's a specification parameter that you sometimes see called CL (CAS Latency) - perhaps Crucial were trying to specify CL2.5 as opposed to 2.5v? It's a bit of a long shot I admit.

You could also check what Kingston suggest for your Dell (www.kingston.com).