You may also find that both sticks or all sticks will test ok when tested individually, but they conflict with each other because they are not compatible when paired. I have seen this with Ram and not the cheap Ram either. I had two 1GB Kingston Sticks brand new not work together and report memory issues with Memtest86, yet they work fine solo. Contacted Kingston and they suggested buying a paired kit for $20 more than the indvidual sticks which have been tested by them as certified compatable pairs, or I can send them 1 stick back and try another stick if I can identify the stick that has the issue spanning to the other.
Guessing that you have Ram that is exactly matched same brand, size, and part number and not a mix and match of say 2 PNY and 2 Corsair of same size and speed. Mixing brands or part numbered sticks can cause issues as well.
