Depends on what you are running for servers. Our primary App is Macess - which is a resource hog - so what the vendor recommended is this For our older ML370G1 ( dual P800) 25 users DL380G2 (dual 1.4) 35 users DL380G3 (dual 2.4 & 2.8) 45 users although we keep em at 35 I currently have 36 servers in the farm - 5 ML370 13 DL380 G2 Balance are G3's 4 of them are 2.8 Ghz Normal user load during the peak periods is about 675