The CPUs are basically from the exact same waver, but depending on how well they pass testing, they get put into a different package (Xeon E5-1400, E5-2400, E5-1600, or E5-2600 (the 1k and 2k series do use a different socket, so you cannot put a 2400 or 2600 in a system designed for a 1400/2400). So their architecture is exactly the same. The only differences are speed (GHz), core-count, cache size, max memory (though if you need more than what a 1400/2400 can use, it's really time to get a dual 2600 system anyway), and whether the CPU supports hyperthreading.
I am about to buy R320 with E5-1410. However I need to clear out one thing. According to Intel support 1410 is OEM product and they cant provide much details. They sent me here effectively. I need to know is there any difference between cache architecture and performance between E5-1400 and E5-2400 ? If yes then I need to know what is it exactly to understand how it could affect my application performance. I need this before I make the final decision.
Please help with info on E5-1410