Are there any benefits to this?
There is the obvious benefit of having more memory to work with.
What are the drawbacks?
- Either all memory access drop to single channel mode. slowing things down slightly, or
- Only this single DIMM will be accessed in single channel mode.
Are there any performance charts the detail what is going to happen?
Dozens, and none tell precisely what will happen because it varies per program.
If you program is CPU bound (that means it is waiting a lot on the CPU) then speeding up memory access will usually not do much. If it is IO bound (e.g. waiting on a disk) then the program will not speed up either. If it is memory bound (e.g. huge matrix multiplication which are way to large to fit into the CPU's cache) then speed can theoretically double.
Theoretically. Practical speed difference for average usage is about 5%.
You will need to balance loss of those 5% (on average) with the speed increase by getting more memory. Usually the extra memory wins. But once more: That differs a lot on what you do.