Just purchased a Mac Pro 1,1. I also purchased additional ram for it. Installed the ram and riser A isn't being recognized. I noticed the LED for cimm 2 is lit. I moved around all the dimms thinking maybe it was a bad stick but it's coming on for all of them. I switch the riser boards and it also does the same thing for the other board. I've done NVRAM reset (Cmd+Opt+P+R), nothing. Is there anything else I can try? Or do you think it's the actual riser board slot?