Well if Windows hangs with all the slots populated, Im gonna say that you probably need more voltage to your memory or northbridge.
I don't agree with this. If it hangs with all the slots populated, low motherboard voltage is not at fault - unless there is some problem or component failure causing the low voltage situation. Therefore, overclocking is not the solution. Either the RAM is the wrong type, there is something wrong with the RAM, or the motherboard has a problem - assuming the motherboard is supposed to support fully populated slots. With the same problem happening with two motherboards, I don't suspect both boards have component failures.
loathe said:
I just saw they have started to charge for this software unless your testing under 4GB.
What program are you talking about?
MemTest86+ is free, unless you know something different (please provide a link). And
Link Removed - Invalid URL from Microsoft is very effective, as is the tester built in to Windows 7.
Frank may have hit the nail on the head about RAM compatibility. While motherboard makers test and list many RAM modules, they cannot list all. So buying off the list does not mean it won't work, but it may not.
Contrary to Athonite's comments, according to your motherboard manual, your motherboard WILL support using only 3 sticks - it just will NOT support running in Dual Channel memory mode with just 1 or 3 sticks. See page 17 of your manual.
The manual also emphasizes to use 4 "identical" sticks - if you want to use 4 sticks.
I also note the following
CAUTION! from your manual on page 8
3. Whether 1600MHz memory speed is supported depends on the AM3 CPU
you adopt. If you want to adopt DDR3 1600 memory module on this
motherboard, please refer to the memory support list on our website for
the compatible memory modules.
ASRock website
ASRock Inc.