I am going to install a heatsink with an extra fan for push/pull, and I'm worried that I won't be able to fit the RAM underneath. You know, the kind with those wacky "heatsinks" like the Corsair vengeance or the G Skill Ripjaw.
Do the heat spreader thingies actually make a difference? If not, I'm not even going to risk buying them and just buy low profile RAM, so I know that they will fit under my CPU heatsink. If they really do make a difference, I'll consider not going push pull and putting the single fan in pull on the other side of the heatsink.
Depends on your version of 'wacky' but the G.SKILL Ripjaws X are compatible with just about any HSF. As far as a difference well that depends upon your use, most 1.50v don't get hot enough to justify tall cooling fins. If you're going to Game or Render for long periods of time then sure even 1.50v RAM can get hot and hot = unstable.
The best solution is an HSF that will accommodate both your RAM and MOBO. Note many of the Noctua HSF don't fit all MOBO's not to mention RAM.
Ideal solution is a Corsair H100 or H80 which offer better cooling, easier to clean and less maintenance. They're factory sealed and easier to install than most HSF. Not to mention they look better than a 'lawnmower engine' styled HSF.
I'm not sure that the heat sinks on ram actually do anything of value, they are supposed to dissipate the heat but I think (my opinion only) they suffocate the chips on the ram. They don't last any longer than regular ram under the same circumstances, I think they are more for show for those users with a windowed side panel.