Dual channel Memtest error

[samtorno]

When I have 4 memory sticks connected I get Memtest errors (#5 test). When I test the sticks by themselves (only one connected) I do not get any errors. When I test only 2 sticks at a time I get no errors (sticks set in proper dual channel configuration). When I test all 4 together I get memtest errors.
What could cause errors to happen with the memtest only when all 4 memory sticks are connected? Is this a memory stick problem or a CPU problem?

All memory sticks are the same brand/speed/everything.

I tested the memory sticks on two different motherboards (Gigabyte 990FXA-UD3 and MSI 870A-G54) but the same CPU (I transfered the CPU and memory between the two boards).

CPU: AMD Phenom 2 x6 1090T black adition.
Memory: G.SKILL snoper 8GB 240pin DDR3 1600 (PC3 12800)
Motherboard: 990FXA-UD3 Gigabyte

Thank you for any advice.

 

[Tradesman1]

Always best to test individually, with multiple sticks can get false positives

 

[samtorno]

Thanks for the advice. I tested the sticks by themselves (no errors) and I tested all 4 together in another PC (I-7) and got no errors. So it would be safe to believe the ram sticks are working and playing nice together.
When I stick them back into my new Gigabyte motherboard with my old AMD processor I still get me test #5 errors (only when all 4 are together), this is most likely a false-positive? I don't have to worry that there is something wrong with the CPU?
Thanks for your input!

 

[Tradesman1]

Try raising the CPU/NB voltage a tad (it's your MC (memory controller) voltage), maybe up + 0.075