Yes, this is the buggiest laptop when it comes to memory I have ever seen.
Went through the same thing as you--perfectly good memory, the laptop just wouldn't take it.
First, is it 2.5 volt ram? Most memory out there is 2.6 volt and none of it will work with you laptop. I tried multiple sticks from multiple manufacturers and spend more money on restocking fees that I would have had I bought the ram from Sager in the first place.
As it turned out, I actually found a local store that sold some off-brand ram that worked just fine--it almost surprised me when it booted up.