Check out this Wikipedia page, it's really detailed... http://en.wikipedia.org/wiki/Linksys_routers#WRT310N
Basically, the CPU is the same speed but different build architecture.
That's all I can see.
Also, you can differentiate between V1.0 and V2.0 by their serial number prefixes...
Version 1.0 starts with "CSF0."
Version 2.0 starts with "CSF1."