Posted 20 February 2012 - 05:49 PM
I have a Custom built computer with 16GB's of DDR3-1333 RAM. The Ram is made by Kingston CPU-z is reporting the part# as: KHX1600C9D3/4GX. There are four DIMMs installed on the motherboard. They came in either one or two kits, I don't recall. I currently have the timings locked in at the BIOS detected defaults and the voltage is at 1.5v. The RAM is overclocked to DDR3-1600.
The motherboard is a Biostar TA990FXE. My CPU is an AMD Phenom II x4 955 Black Edition. The Processor is currently overclocked to 3.9Ghz with a multiplier of 19.5 and an FSB speed of 200Mhz (this is stock). My PSU is 430W.
Now for the problem. If I try to change the FSB to anything higher then 209Mhz one of my RAM DIMMs stops working, anything higher than 223Mhz and a second one cuts out. I haven't tried setting it past 230Mhz, and at 230Mhz I still have two DIMMs available. The amount of available RAM changes to reflect this at the BIOS level. CPU-z, after booting into Windows, reports my machine as having only two or three RAM slots filled, as if the DIMMs that cut out just aren't there at all. If I try setting the FSB back down to stock the RAM shows back up as if nothing happened.
Do I need to adjust the timings on the RAM? Is the PSU a factor at all? Do I need to change RAM voltages? Why is this happening?
Oh, and I should probably mention I'm doing all of my overclocking from the BIOS, not from any sort of program inside Windows.