I upgraded from 8gb of ram to 16gb today for no reason other than it was cheap.
Interestingly enough, my heaven benchmarks have changed:
8GB
16GB
I haven't changed any of the settings or changed drivers but my minimum fps has increased. The only difference is in the first screenshot, heaven incorrectly identifies my GPUs.
Min and max aren't useful measures unless you've got a chart graph plotting FPS compared to time. A slight dip for 1 frame would make the comparison pointless (plus, you also need to run the benchmark several times so that it kicks out other data from previous apps you used).
I think the random read speeds of an SSD make the pursuit large chunks of RAM a moot point for everything except for professional work (video, audio editing, anything with tons of assets) and virtual machines. The only reason to have lots of RAM is because reading from the disk in the past was tremendously slow considering you have to wake up the drive, seek to the location you want, read the data into RAM at 100 MB/sec before anything gets done.
Now when seek times are 0.1 ms (basically pointless to measure with SSDs) and sequential read speeds at 500+ MB/sec, you can fill the entire contents of 8GB of RAM in 16 sec, something that would have taken 13 minutes on a typical hard drive.
All of this is a way of saying, save your money and buy an SSD. The SSD isn't really the bottleneck as much as the CPU and GPU are these days.