Ubuntu :: Memory Density With Recently Purchased RAM?

I recently purchased some RAM from ebay and discovered what appears to be one stick is bad and one is good. The purchase was for 2 X 1 GB. My mother board is supposed to support 4 X 1 GB for a total of 4 GB, and there are 4 slots on the board for RAM. It is PC 3200, 400 MHz, 184 pin and that is how the item was listed. I ran multiple tests on the RAM sticks I purchased as well as the RAM I have the came with the machine (when I purchased the machine used). The machine worked fine when I purchased it and one of the RAM sticks I purchased is currently in the machine along with the original ram (total 2 X 256 MB + 1 X 1 GB) and works fine. It is just that one stick that is problematic.

Now, in the most recent email the seller sends me, he claims the density of the memory is not correct and that is the reason the stick does not work. This does not make sense to me for a few reasonts:

1) If the density is not correct then how come the other stick works fine in there? 2) Why then does memtest86 (run on that actual machine, through that mobo) show one of the sticks as passing with flying colors and the other as screwed up every which way from sunday? 3) If the manufacturer's specs on my mobo says that it has 4 slots and supports a total of 4 GB with 1 GB sticks in each slot, then how can density be an issue (note: there are 8 dram chips on ea stick of this memory I purchased).

I see that, according to ebay's buyer protection policy I have 45 days from the date of purchase and the RAM was purchased 22 days ago (I'm about in the middle of that time period). I still have some time to resolve this but I was hoping to get some feedback from you guys to help me make sure I'm on the right track and that the situation with the RAM really is as I believe it is.

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