Bad Ram MacPro 3.1

[dobro03]

I have a 2008 Harpertown 3.1 MacPro 2x2.8 GHz Quad-Core Xeon. I'm the original owner and it has been steady as a rock. The last 4 years I have been running Snow Leopard 10.6.8 and all is well. A month ago I upgraded the Mac to an internal Samsung 1TB SSD and things felt much 'snappier'. About 4 days ago, I cloned my OS drive and then upgraded my OS to Mountain Lion 10.8.5. I did this because I need ML to run a few updated music software programs that wouldn't run on Snow Leopard.

Everything was fine till today. 3 times today, the computer just turned off. I checked 'About This Mac' and 2 of my RAM modules are now listed as empty and I have 8 gigs less RAM now. Does this mean the modules have died and it is just a coincidence that it happened when I changed the OS? Should I check something else? I ran an older version of Tech Tool and it said the RAM was fine.

Suggestions?

Thanks

 

[OS6-OSX]

Check page 44 of the Mac pro early 2008 pdf for ram configuration
Use compressed air and spray where the ram seats
Make sure you power supply unit is clean
Time for a spring cleaning?

 

[m4v3r1ck]

Reseat your RAM modules

Reseat your RAM modules in a different (random) order, depending on the number of modules you have placed. Make sure you pair (same X RAM modules) them as the screen below shows.

If needed doing some housekeeping inside you MP regularly is always a good advise!

Good luck!