RCBH928 wrote:I have a computer with 4GB in one slot and 2GB in another slot, does it make a difference that they are not exactly equal?
It does make a difference. Multi-channel memory requires identical DIMMs in corresponding slots (why you often see two different colors for RAM sockets). Each pair/etc doesn't need to be the same. For instance, you could have 2x4GB and 2x2GB and it'd be fine. Also keep in mind that all the RAM in a system will run at the same clock/timings, so if you're mixing and matching, your lowest spec DIMMs are going to determine what it all can run at. The
ideal thing is to buy matched sets of DIMMs.
Keep in mind that you can end up running into compatibility issues with RAM, so it's best to check to see what configurations and kits have been tested by the PC/motherboard manufacturer. It's not likely to be the only stuff that'll ever work, but it can give you a good idea.
Also, again, this is what's ideal, and there can be a difference in performance. However, outside of synthetic benchmarks or particular workloads, it doesn't tend to be
that big of a difference (less than 5%). Can see some testing
here for instance - up top, the big difference in synthetics, and then the relatively minor ones when you get to most actual tasks.
For day to day desktop type use, at least to a point,
more RAM is likely preferable, or like that article says, better performing memory. Though, typically, you're probably going to wind up buying a pair of DIMMs anyway.
If you're looking at upgrading a laptop or something though, again, dual channel memory at the fastest speed it'll support offers a noticeable boost to integrated graphics.
