I put a Coolermaster Jetflo in. With the Coolermaster V8 you just undo the four bolts holding down the top, the bottom two screws holding the fan, and the top and fan slide out...

I now have the Jetflo working in silent mode - 19db as opposed to 36db on full. It's only added 2°C to the CPU temp so that is still much better than before.

My PC isn't exactly quiet to start with. Being a gaming PC it has more fans than Taylor Swift The loudest noise though is a high-pitched whine from the GTX760.

I can +1 Noctua!

I have a Nanoxia DS5 filled with NF-14's.  There are quieter fans, but these actually stay quiet for more than a year, I replaced the H110i GT fans with the Noctua's as soon as I installed it, massive difference in sound even if it is moving a little less air, and my CPU stays below 47C at a heavy overclock running Prime95.

The two Nanoxia fans that came with the case though are, so far at least, super quiet.  They're moving even less air, but damn near silent.  I'm keeping them in to see how they do over the long term, if they stay this quiet I'll probably trade out all of them for more Nanoxia fans.

I dispensed with heatsinks and fans a couple of years ago to try liquid cooling and haven't once looked back.  In one machine I'm using the Corsar H110 liquid cooler, and in my main rig I'm now using a Deepcool Maelstrom 240, which is highly efficient.

BTW, Paul/Jafo, if you were to also switch to liquid cooling, you'd be able to populate all 4 of the lefthand side DIMM slots that are currently vacant due to the heatsink and fan occupying the space above.

Maybe today, but who knows the future demands of the Win 10 abomination?

Nah, if you're happy with the RAM you've got that's all that matters.  I have 32G of G-Skill 2400 and find it more than adequate in my Intel machine.  I also have 32G of G-Skill 2133 in my AMD rig, which really kicks butt.