The first step of the build was seeing whether or not I could fit a custom loop into the case without adding a top hat - I'm just not a fan of the look. Here's the longer original post on reddit but here's a summary of what I think are the important things...
Since the main point of the build was to explore PCIe bifurcation, I probably approached a custom waterloop from a different perspective than most. I'm not trying to reduce temperatures or noise - I'm trying to reduce space taken by components. That also means I'm pushing temperatures and fan speeds higher than most other loops. I ended up with a custom loop for my GPU only on a single 120mm radiator and I think it worked out perfectly. Here's a picture of the initial GPU only loop and some of the cut outs needed into the case to make things fit:
[MEDIA=imgur]a/5M6cx6V[/MEDIA]
Overall I considered this a success. GPU temps and noise where both down from the original stock cooler, and the liquid temps were with in safe ranges. Here's a quick part breakdown for that original loop:
GPU - Radeon RX 5700XT Reference card
GPU Block - Watercool Heatkiller IV
Riser cable - LinkUP 25cm PCIe 4.0 Riser with 90 degree socket
Bifurcation board from C_Payne
Radiator - Magicool 120 G2 Slim w/ Noctua NF-A12x15
Pump - Alphacool DC-LT w/ Plexi pump top
Tubing - Tygon E3603 6/10mm tubing
One thing to note is that I really recommend 6/10mm tubing for any SFF builds. I still don't understand why everyone uses 10/16 tubing still... it just seems like royal pain in the ass.
I initially thought this would be as far as I needed to go but I couldn't get the GPU to run at PCIe gen 4 speeds. That kinda defeated the purpose of bifurcation in the first place so further down the rabbit hole I went...
