MacPro Memory Upgrading Issues

[memmullen]

I have just updated my Mac Pro Dual-Core 2.8ghz to have 16gb of memory. I now have 8 x 2GB sticks in each slot. For some reason or another, the computer is only seeing 10GB of ram rather than the 16gb total.

I've double checked to make sure each stick is inserted correctly, and even went as far as rearranging the sticks in a different order to make sure there wasn't a dead stick.

I went into the system profile and see that two separate sticks are only showing 1gb rather than the 2gb installed.

I've refreshed/reset the PRAM and really can't think of anything else to try. Any Mac genius out there know what the issue could possibly be? Thanks for any help.

 

[dr. shdw]

Bad memory/slots? Try putting just half of the sticks in at a time and see if it recognizes all of it.

 

[tobyg]

8x2 is pretty easy, no issues figuring out pairs and such really.

But your math isn't adding up. 8x2 = 16, yes. But you said it's only seeing 10gb. Does that mean it's seeing 4 2's plus seeing 2 of the 2's as 1's and the other 2's aren't being seen at all? Or is it seeing 6 sticks as 1GB and only 2 as 2gb?

Have you swapped the riser cards? Does the problem follow the riser slot or the riser card? What does your system profiler show exactly?