I don't think Dell ever made a BIOS update with support for Xeon E5 v2 processors. I had this question back in the days and this was the answer. People who tried inserting a v2 processor ended up with a system that failed to post.

Hi back

Sorry for the late answer. So should i buy a dell t5810 motherboard ? Does it fit to the t3600 and also do the t5810 support the e5 1650 0. I am gonna probably take one month before buyung the e5 1650 v3. Thanks

@TheQuickFox 

Please pardon, I accidentally marked a post as a solution while trying to scroll.

It looks like an MB swap might be possible if front and rear panels are the same.  Dell is very proprietary, so no guarantees.  Pull up a T5810 spec sheet and it just says "5810" and it shows me a completely different looking model.  But if I just Google it, it looks the same as the T3600.

Please see screengrab: