>Getting two used boxes for a great price. I'm going to cannibalize one to feed the other for memory, extra hard drive, etc. I'll keep the eaten one for replacement parts. Is there something I can do to know which one is "better?" They both have the same processor, etc.
Probably not much difference. If they are from different manufacturers, you can get information about the manufacturers. You could do some speed tests. The real difference is likely to be durability - one of the two will fail earlier than the other. But I don't think there is a way to figure that out.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)