Memory/BSOD issue with MB 790XT-G45

Question

System Specs:
MSI MB 790XT-G45 (ms7388)
AMD Phenom II X4 940 processor (AMD heat sink)
EVGA GTX 460 Video Card
Crucial Ram  BL25664AR80A.16FE5
DDR2 Ballistix - PC2-6400 (800MHz)
SPD (default) Timings = 5-5-5-12
Maximum Timings = 4-4-4-12
Voltage= 2.0V
4 sticks 2gig each
HDD:
WDC WD500AAKS-00V1A0 ATA
WDC6401AALS-00L3B2 ATA
PSU:
OCZ-ZS750W
Pioneer DVD DVR 108
Full size case
Windows 7 Ultimate 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.110622-1506)
I recently updated Ram and Graphics card several months back. I began having random BSOD and have been trying to track down the issue.
First thing I did was update my PSU from 500W to the current 750W.
Second thing I did was to run a chkdsk. Then I ran Western Digital’s hardware check and the HDD came up fine.
I ran heat check programs to monitor heating issues all came up fine.
Next I pulled half the Ram and ran for several days with no issues. I assumed Ram was bad. Ran memtest 86 individually on all 4 sticks and they all tested fine.
Finally I ran Furmark to test the graphics cards and it stressed tested fine.
I made some queries on some tech forums and this is what I was told:
“Filling all the RAM slots on a Mobo can cause Voltage issues and that appears to be your problem.”
Is this true? Do I have 4 slots but can only use 2 of them? Every single time I put in 4 sticks I get persistent BSOD several times a day. The moment I pull 2 sticks it stabilizes. Is this an issue you can help with?

Answer 1

Hi seanchai,
You can do this. It is a lot of steps, but each one is simple and You Can Do This. :-)
I suggest you start with 2 sticks of RAM. If your system works with the 2 sticks and changed timings,
then install the other 2. Or you can install all 4 to save time and hope for the best.
When you first turn your computer on, hold down the "Delete" key. This gets you into the BIOS utility.
Once there, use your arrow key that points to the right, to move the selection highlight to "Cell Menu",
then press the "Entry" key to select it.
You should now see a lot of options related to your CPU and RAM. Use the arrow key that points down
to move the selection highlight to the "Advance DRAM Configuration" option, then press the "Entry" key to
select it. At the top of the options you now see should be "DRAM Timing Mode". This allows you to select
"DCT 0" to setup timings for your 2 A channel RAM slots, or "DCT 1" to setup timings for your 2 B
channel RAM slots, or "Both" to setup the same timings for all 4 of your RAM slots. Use the "Page Up"
or "Page Down" keys to cycle to the setting you want. I suggest you select "Both", if both your pairs of
RAM have the same timings.
Now the next 4 options correspond to the first 4 timing values in the Timing Table you posted earlier.
CAS# Latency = CAS Latency (CL), RAS# to CAS# = tRCD, RAS# Precharge = tRP, and tRAS= tRAS.
The tRC in the Timing Table is equal to tRC in the list of options. Use your arrow keys to move to the option
you want to change from "Auto" to the value in the Timing Table. Use the "Page Up" or Page Down" keys
to cycle to the value you want. I suggest you use the JEDEC #1 values at first, so that you do not have
to change the RAM voltage values. After you have selected all these values, press the "ESC" key to return
to the "Cell Menu" page of options.
Use your down arrow key to move to the "FSB/DRAM Ratio" option and use your "Page Up" or "Page Down"
key to change the ratio so that the value displayed below this option is as close to "666" as possible (double
the "333" value in the Timing Table). It may display "667", I do not remember.
Use your down arrow key to move to the "Auto Disable DRAM/PCI Frequency" option and use your "Page
Up" or Page Down" key to select "Disable". Then use your down arrow key to move to the "Spread Spectrum"
option and use your "Page Up" or "Page Down" key to select "Disable".
Now press to "F10" key to save all these changes". You will get a prompt basically asking if you are sure
you want to make these changes. Select "Yes" and your computer will reboot and try to use the changes.
If the changes you made are in an "acceptable range", the computer will start Windows, if not it will stay
on the boot up screen and tell you what you need to do to fix things.
Once back in Windows, run CPU-Z and check the memory tab to verify the changes you made are in effect.
Then run your stress test or whatever you did that resulted in a BSOD to see if it still occurs.
Standard RAM frequency, timing and voltages values are set by JEDEC. Non-standard values (EPP) are set
by each RAM vendor for their products. All motherboards are designed to automatically set RAM to the 'best'
JEDEC values the board can support. The JEDEC and EPP values (if any) are stored in a special chip (SPD)
on each stick of RAM. In some cases, if you want to use the RAM's EPP values you have to set them yourself.
Some boards can also be set to automatically use EPP values.
Unless you use the motherboard and RAM that AMD suggests for the CPU you have, you need to sometimes
make adjustments when you use 4 sticks. Sometimes you need to make adjustments even when you use
products suggested by AMD. Most people do not use 4 sticks or buy systems already setup, so vendors get
away with not fixing this problem for the average user who upgrades or setup stuff for themselves.