Not much obvious information on the net on this one - in fact, it was a surprise to me that the 12-bay R515 even had internal 2.5" cabled drives.
We're considering sticking in a couple of high-speed SSD drives in there but need to know whether the interface is SATA-2 (3Gbit/s) or SATA-3 (6Gbit/s). We're hoping the later! Can't easily have a look inside as this is our production SAN.
A (very) quick search finds a Dell page about the machine (http://www.dell.com/uk/enterprise/p/poweredge-r515/pd) which suggests SATA3 in the default configuration (all the I/O rates are quoted as 6Gbps. To be sure though you will need to check with Dell, the documentation that came with the machine you have, or your supplier. You may not have the default I/O controller(s) (you could have specified a better/different add-on RAID controller when you bought it for instance) so you'll have to check that.
If you have a SATA2 controller you can still used SATA3 drives and vice-versa, so whatever combination you end up with the interface will just run at the speed of the slowest (6Gbit if both controller and drives are SATA3, 3Gbit otherwise).
