  Yes, all revisions will work in every chassis. All revisions are backwards compatible, so if you are installing a newer board everything should continue working normally. If you install an older board then it could cause issues.
I have two PE R805 servers and four Opteron 2435. On one server all four processors work in each possible combination. However, when i try to use the same processors in my other R805 it will not bring up a VGA display of boot and sits idly and doesn't appear to boot. There are no POST messages or errors on the LCD display. Do only certain models of the R805 (Different motherboard part numbers) support the hexacore opteron platform? The problematic R805 came with 2x Quad-Core AMD Opteron 2360 SE chips.  Any and all assistance is greatly appreciated!
PowerEdge R805 and Opteron 2435