So I just built a new system
CPU: AMD Phenom II X4 965 BE
Mobo: Asus M4A785T-M
RAM: 4GB OCZ DDR3 PC3-12800 / 1600MHz
HDD: WD Blue 640GB (Taken from a working computer)
PSU: Antec Earthwatts 500W (Taken from a working computer)
Using onboard video for now.
The thing always crashes/freezes
I've been using memtest86 to test the memory because I think that's the culprit since the CPU does not natively support 1600MHz.
When I run memtest on each stick separately, it passes the test.
I have been able to keep the system up and running overnight with 1 stick of RAM installed.
When I have both sticks of RAM installed its a separate issue.
The system will freeze on me anywhere from 5mins after booting to about a few hours.
When I run memtest, it fails about half way through the second test.
I have tried different memory frequencies. I have tried making it run at DDR3-1066, DDR3-1333 and DDR3-1600 and they all crash at the same point in the test.
I have tried all sorts of different RAM slot combinations.
I have tried taking the from another computer and stick them into this system.
Same results one stick works, 2 sticks crashes
Okay I just over volted the ram to 1.68v instead of the 1.65v stock volt
Still fails memtest but its not freezing anymore.
Will try reseating the CPU tomorrow when I get some more thermal compound.
At the risk of sounding stupid - What is the exact model number or you OCZ memory? Because I'm finding that some of the OCZ memory like OCZ3P1600EB2GK takes 1.9V and these OCZ3G16002GK, OCZ3G16004GK take 1.8V while these OCZ3P1600C9ELV4GK only take 1.35V. So if you tell me the exact model number we can put into account that your up to 1.68 and it's actually running better. You might need to go up to the 1.7, 1.8 or 1.9V to get them to work correctly. I don't see any OCZ listed on the Qualified Vendors List for the 1600MHz but on the 1333MHz I see these listed.
OCZ OCZ3P13334GK DDR3 1333 4096MB(Kit of 2) 7-7-7-20 1.8V
OCZ OCZ3P13334GK DDR3 1333 4096MB(Kit of 2) 7-7-7-20 1.95V
Both, as you can see, have voltages well over the 1.68 that you are currently running. If you are using these last two and since they are on the QVL as supported at those voltages then it's ok to bump it up to that. If you have something that's not on the QVL you might still be able to bump it up but you should be careful and first look up your exact memory modules' model number and check the operating voltages. Does OCZ have it's own compatibility list that guarantee yours to be compatible with that motherboard? If not I would seriously consider getting memory from the QVL or Corsairs Configurator. This will give you several different choices and they are in the 1.5V to 1.65V ranges you are shooting for.