I doubt if there's ever been any anand-level testing done on a partitioned SSD, but from what we know about SSDs, there is no reason to believe that a multi-partitioned SSD could possibly perform better. As long as you keep 25% or more free space it will perform optimally.
The only way a two-partition SSD would perform better is if you have a virus scanner set to only scan/protect your C drive, or maybe something like microsoft's indexing service only indexing the C drive. (But of course you shouldnt be indexing an SSD anyway.) But that is clearly cheating.
One good reason to partition your SSD is actually one of the best reasons to partition ANY system drive: to keep your boot partition ghost/backup images small so they fit on a 16GB/32GB thumb drive. My boot drive is currently 36GB, but thanks to compression and the ignoring of pagefile+hiberfil, it fits nicely onto my 16GB flash drive.