There is no 1:1 ratio with 1366, 1156, or 1155.
Still matters on all platforms for Super Pi and the like.
Amount of memory wouldn't do anything for me, but quicker memory makes a huge difference. For a super 32M run, a kit of Elpida Hypers can shave off 10-15 seconds. For Geekbench, it can raise my score ~1000 or more points.
These sticks are 1800 6-6-6 17 1T 32M stable and 2133 7-7-6 19 1T Geekbench stable. I'm sure I can do 32M at 2133 7-7-6 19 as well, but unfortunately my CPU's IMC can't do it as Super Pi 32M is one hell of a load (and it takes a long time).
If Elpida made 3x1GB Hyper kits, I probably would have purchased those. If they did, I never saw them!