Memtest errors only with all 4 RAM slots used

[ewillyb]

(Note: I was forced to pick a sub-category for this post that is N/A.)

I'm getting lots of BSODs. Memory dump points to a different process each time so I figured it was the RAM.
Running memtest with all the RAM (4 x 2 GB G.skill 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500)) produces errors almost immediately. Testing with a single pair yields no errors.
Testing with the second pair only yields no errors.
I will be switching slots this evening to rule out defective slots.
But could it be anything else?
I'm not overclocking.
My rig:
- MB: GIGABYTE GA-EP45-UD3R LGA 775 Intel P45 ATX Intel
- CPU: Intel Core 2 Quad Q9550 Yorkfield 2.83GHz LGA 775 95W Quad-Core
- Win 7 Ultimate 64 bit.
- 2 HDs which had been set up as RAID 1. But which no longer are.

 

[stingstang]

Best guess is a faulty memory controller, or RAM slot. If not, and you already checked the RAM for DOA's, then it's gonna be a mystery.

 

[bucknutty]

ddr2 ram is quirky at anything over 800mhz because you are exceeding the voltage per stick in the ddr2 spec.

Just for fun try setting the ram manually to the 800mhz settings and timings that gskill lists. Then try memtest. I bet it will run fine.

In reality the 1066 ram only gives a total system speed improvement of like 1%.

I bumped up the FSB on my ram by like 10mhz at a time to try to get up to 1066. Never got above 1000.

 

[ko888]

What Command Rate are you using for the memory timings?

With four memory modules you may have to use 2T/2.5T but if you use 1T you will have an unstable system.

With two memory modules you may be able to use 1T depending on the quality of the memory chips.

 

[ewillyb]

I will try that.
I'm a bit of a hw noob.
I naively thought that, as someone that does not over-clock, I simply needed to select identical RAM sticks compatible with my mobo and snap the suckers in.

 

[AntiZig]

you were not wrong with that, in most cases it should work fine

 

[ewillyb]

Thanks to all for the suggestions.

Once I determined that it was not faulty RAM or RAM slots, I dove into the RAM tweaking in the BIOS.
Found a post by a guy with the same mobo, RAM, and problem who said that G.Skill told him to change DRAM voltage, command rate, and a couple of other things to try.

FYI, changing RAM speed from 1066 to 800 was not an option. This speed is calculated and read-only (at least in my set up).

In any case, the above tweaks allowed memtest to pass with all 4 sticks and, to date, I have not experienced any BSODs.

And I learned a heck of a lot about tweaking. Thanks again.