I have no idea my mac pro always get some problem, today I have Rams problem need your help.Thanks Early 2008 Mac pro 2x CPU 2.8Ghz 4core each, I have 2x1GB Rams(Factory come with system) I bought 2x2GB RAMs from 1-8004Memory.com. I am using these 2 rams for about 1 month and today got problem，when I only installed these 2 RAMs(2x2GB) the system only shows 3GB total sometime only shows 2GB (1GB each but it's 2GB ram) and only showing up Riser B slot 1&2. I 100% sure put each Ram(2GB) on both slot 1 Riser A&B. When I try to follow mac pro Rams rule put factory Rams(2x1GB) on Riser A slot 1&2 and 2x2GB on Riser B slot 1&2 the system only gets 2GB from Riser B slot 1&2 other slots on Riser A & B are empty，what's going on here? Does any Rams has problem or what? BTW first time I using RAMS on the wrong configration which I put 1GB+2GB on Riser A slot 1&2, same as on Riser B. I jsut realized yesterday that I did wrong way so when I try to follow the Mac pro Rams way but has troubles any ideas? I think maybe my additional 2 2GB RAMS which I bought from third part have been damaged. I test in system all these 4 rams can pass(start while press D key for testing ) I attached 2 pictures the second one shows 2GB total 1gb each from Riser B slot 1&2 are my(2x2GB RAMS third part but they are OEM which are the same rams chip) why they only shows 1GB for each and my factory 2x1GB Rams on Riser A slot 1&2 are shows empty. I have 3 years apple care when I bought this 1.5 month ago,can I bring to apple store let fix for me I think I use the third part RAMs does it matter or not.thanks Thank you for your time and help me to fix this problem.