Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

It'll take a little long to describe my situation but here goes the story :

In January 2009 we bought (the OEM parts) two similar systems with just one difference. One of them had a Phenom X4 CPU and the other one (mine) a Phenom X3 CPU. At the beginning we had problems with both systems to power them on whilst having all of their ram slots being full. We decided to install the systems with just 2 or 3 slots populated and later try to install the rest of ram sticks. Both systems did succeed to support 3 sticks. We tried many different procedures to make the systems work with their fourth ram slots being populated. We waited for new bios updates and flashed the boards when they were available, we tried different ram sticks with different frequencies etc. One day while we were trying to install the fourth stick, the X4 machine did accept it. The other one did not. The most mind boggling thing was that after one of my trials the X3 system begun to not operate with the third slot populated. Our boards did have AMD 770 chipsets and we even tried to change the board of the X3 machine with another 770 chipset board. (This change did not allow the system to use the third ram stick again which is another mystery.) Now my questions are :

  • Should we change the cpu ?
  • What is causing the X3 system to not accept the fourth (or now the third) ram stick ?
  • The manufacturers sites do claim that this boards do accept 4 ram sticks of 2 GB size (but they only tested them with certain ram brands and models). What are the limitations for maximum ram configurations on motherboards ? Are there some "rules of thumb" except frequency, voltage, chip type considerations for which we did check our parts ?

Our boards are :

  • Gigabyte GA-MA770-DS3
  • Sapphire PC-AM2RX780 - PURE CrossFireX 770

P.S.: I forgot to mention that we are using 2 GB modules which means that the X4 rig is using 8 GB right now. X3 did succeed to operate with 6 GB at the beginning but now it doesn't go further than the POST screens with 6 GB of ram.

share|improve this question
    
What power supplies are you using? Some boards are not compatible with high-efficiency power supplies, and will behave oddly as a result. –  GalacticCowboy May 18 '10 at 15:48
    
We tried 3 different PSU's with no success. –  Enmos Proje May 18 '10 at 16:04

2 Answers 2

I had the same issue with my last computer, I don't remember the motherboard type but it too was a gigabyte. It would not boot if I had memory in all four slots.

I fixed it (sort of) by lowering the memory-speed in the BIOS. Not ideal but I figured slightly slower 4GB was better than 3GB.

share|improve this answer
    
We tried that too with no success. Btw we are using 2 GB modules as I've added to my post. –  Enmos Proje Apr 27 '10 at 16:33

Have you tried to update to the latest BIOS for your motherboards? That often helps with hardware compatibility issues.

share|improve this answer
    
As I mentioned before : We tried many different procedures to make the systems work with their fourth ram slots being populated. We waited for new bios updates and flashed the boards when they were available, we tried different ram sticks with different frequencies etc. –  Enmos Proje Apr 28 '10 at 9:20

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.