Strange memory problem

[surflordca]

I have an Early Mac Pro with 10 gigs of memory. The 2 from Apple and 8x2 gigs from OWC. For 4 months all was well but now RISER A slot 3 & 4 only show 1 gig each instead of 2 gigs. What would cause this? I ran the program Memtest V4.21 and it passed. Would this be a computer problem or a memory problem? Would Apple care as I didn't buy the extra memory from them

 

[CanadaRAM]

First try repositioning your RAM

The four 2 GB modules should be in Riser A slot 1 and 2 and Riser B slot 1 and 2
The Apple RAM should be in Riser A slot 3 and 4

 

[surflordca]

First try repositioning your RAM

The four 2 GB modules should be in Riser A slot 1 and 2 and Riser B slot 1 and 2
The Apple RAM should be in Riser A slot 3 and 4

I am sure that is the way it is. I will remove all ram and reset. Thanks for the info.

 

[surflordca]

Well I think I figured out my problem. First let me fill you in on what memory I have.
2 x 1 gig from Apple
4 x 2 gig from OWC
Bought this system Jan.9/08 when released.
My early 2008 Mac Pro showed all 10 gigs up to about 3 weeks ago. Now it shows only 8 gigs. I never had time to work on it until now. On the advice of Canada Ram I switched around my ram. Still the same problem and some times even worse as the computer never even seen 8 gigs.
I have a red light on RISER A so I moved RISER A to become RISER B and configured the ram correctly. Now RISER B has the red light. This is the riser that doesn't show all the ram. I ran Memtest v4.21 and all passed.
So I am thinking that I have a bad RISER card.
QUESTION:
How will Apple deal with this. I sure hope that I don't have to lug the computer 70 miles away and than catch a subway to get to the Apple store.

 

[surflordca]

I just called Apple. They are shipping me a new RISER card. I don't have to take my computer in

 

[surflordca]

Update. Problem fixed

I received a new Riser card from apple and had the same problem as before. So I had to once again start tracking down what ram was bad. Once I got this figured out I called OWC as it was one of there ram sticks. The service that I received from OWC was 110%. I got an RMA number right away. Was told to send back not only the bad stick but also the good one so I can be sure that I have a matched pair. By the time I sent this back to them and received my new ram it was 7 business days. Now remember I live in Canada so this service is GREAT. Would I recommend OWC, you bet ya.