all I can give you is my 2cents. I have the same kind of Mac pro you do, and here's what did it for me: There is a certain way to install the Ram modules, the mac pro "prefers' it like that. Usually matched pairs. You could also try memtestosx.org
here is a link to apple's installation diagram
maybe the riser is bad, but that could be premature...I may be wrong
anyways, follow the diagram and you may be successful... I think you may have to shut down the Mac pro before swopping risers.... then again, you may have bad ram, or not
Thanks for the response, however the Ram on both cards is recognised when installed in Riser B but neither card is recognised in Riser A as I pointed out in my first post. Which would suggest that the problem lies with the Mother Board / Riser connection. I also mentioned that I recently had to swop out the Graphics Card as the original had died is there a connection from Riser A that could have been dislodged during installation og the new card? I suppose I'll have to take the thing apart and have a dig around.
What graphic card? you had 7300GT and put an ATI 5770 in and connected the power cable w/o trouble?
No, had some power issues, computer would randomly shut down to begin with but after a full SMC reset the ATI 5770 has been fine.
The top slot for a Riser then, even after replacing with a new one?
And where did you buy the new Riser?
Have not replaced either of the risers?
Ram is a mix of Crucial and Kingston and was all working prior to Graphics Card being replaced.
OK! So I have run a Hardware test which shows I have all 14Gb of Ram physically installed in the appropriate risers but only 8Gb is shown to be actually working. Thats the 8Gb installed on the card in Riser B. Can anyone explain that?
Apologies, I think I may have confused the issue somewhat with my incorrect use of nomenclature. When I referred to the Riser I thought this was the socket, I now realise that the term Riser refers to the Card on which the ram is installed.
So just to recap both Riser Cards work, as does the Ram installed on them, however when either of the riser cards are installed in the top socket they are not recocognised. So the problem in all likelihood is a dodgy socket A!!!