Yeah it would probably speed up the CPU's ability to send rendering data to the GPU a little, but you'd have to go with at least 1600 speed RAM to see a difference. The reason being is your CPU is a bit old too. 1600 has always been the sweet spot for DDR3 though. Beyond that the speed benefit drops off quite a bit.
Note that you will have to put your MB BIOS in XMP mode to get the rated speed out of the RAM though. Otherwise it will only run at 1333, which is same as 665 btw. Your BIOS only shows one half, but it actually runs at double that speed.
The thing is though, if you can save up more or have been considering a CPU, MB, RAM upgrade, I would advise that, especially since holiday deals will be here soon.
Before you do all...