I didn't really build this for the silence, but when I added my CPU to the mix. I was like huh that's pretty damn quiet. If I'm not bios or MPT level OCing my GPU my PSU fans are my loudest component. Even then I haven't really tried to to OC as quiet as I can. It's ugly right now, if I keep it like this I'll throw the tote in my closet. I have a sheet on it to keep the dust out. Almost 3 months no growth.
50 gallon tote of water $12 Walmart
40 Gallons of Distilled water $30 or so
Aquarium water pump $15 Amazon (1 year warranty)
2x Water block $15-20 Newegg Ebay Amazon
Tubing 3/8 ID $10 Home Depot 10 FT
Brass barb for the water pump $4 Home Depot
Compression fittings for the blocks $20
Alpha Cool Heat sinks 14 mm $20
Thermal glue $3 Amazon (Don't put thermal glue on your core)
Z9 Deep Cool Thermal paste $10? 3 grams Ebay
Bolts n wingnuts under 10$ Home Depot\Ace Hardware
All prices are with shipping included or few dollars within.
I'm using a CPU waterblock on my GPU and one on my cpu. You could use a quiet 120 mm fan for the memory. But I made a little cardboard blower to replicate my GPU's original design, with some heatsinks.
BUY A GPU WATER BLOCK MOUNTING A CPU WATER BLOCK ON A GPU SUCKS $17. Or you can buy a proper water block designed for your GPU.
Anyone who wants a silent computer should probably just use a thunderbolt cable like Linus Tech Tips and place your rig in a distant closet. Even a USB extension cord\long DP or HDMI cord. Use boot by pressing a keyboard key.
P.S. If you want to make mounting easy on blocks that do not match what your using, get expansion washers, like these smart people from China. My GPU stays below 48c, I had it under 40c at one point even at 2050 core 960 ram. But I cranked my mounts to much, chipped the edge of my GPU core and I'm out of good thermal paste\patience atm. My CPU stays under 55c gaming. I used some super super old maybe 10 year old thermal paste on the CPU, old cool master tube. Ambient 26c. I need to get some expansion washers and remount to OC higher with lower temps.
GPU 2030 core, 955 ram gaming stable, 5700 non xt, 1.2v, 50% max power
CPU 4.1 ghz, AMD 2600 gaming stable 1.37v
P.S.S. I bought some other stuff too, but this is what I actually use.