Question First timer question about rads for an O11D XL build ???

Feb 11, 2020
TL;DR - I need recommendation for how many (2 or 3) and which rads (GTS, SR2, etc.) to use with an O11D XL case with noise level a main concern (3900X & 2080ti or next gen equivalent).

I've built a few PC's but I am planning to do my first water cooled build later this year (probably after RTX 3000 series comes out). I want to build in the O11D XL case and plan on having 10 Corsair QL fans. (My 10 year old daughter is helping me for her first experience building and is enamored with RGB lighting.) I am trying to figure out which rads and how many to use. I obviously want performance, but a major concern is noise. The PC will be located on top of a desk in our living room just behind the couch where people will be sitting watching TV, their heads only about 4 feet from the computer.

If I was building right now it would most likely be a 3900X with a single 2080ti, but I'll probably be using the 4900X, 3080ti equivalents, or whatever they end up being called. Looking at a single loop but open to doing a dual loop.

I originally considered using 2 HWL GTS 360 rads (bottom intake, top exhaust) with three fans intake on the side and one exhaust on the rear. The original thought was to get fresh intake on the side to help cool the VRM and NVME drives (x2). However, when thinking about keeping noise down, I thought maybe if I had a third rad on the side as intake, I could run the fans slower overall. But, last night, I read about the resistance the rads put on the coolant flow and that adding a 3rd rad might mean I have to run the pump (D5) higher which makes it louder. So, I read a little more about the HWL SR2 rad and how I could run low fan speed on that without as much of a resistance to coolant flow. After so much reading through threads and conflicting info, my head is starting to spin a little.

Can someone give me a recommendation on how many and which rads (GTS, SR2, etc.) would work best for keeping the system quiet? I am open to getting extra fans (noctua or other) to run in push/pull if it fits, but as mentioned above, looking to use Corsair QL's on the interior face for the daughter interest/approval factor.

In the mean-time, I have my heat gun and some hard tube to practice bending with...


Mar 27, 2019
Two 360 radiators are more than enough. I would suggest running both radiators as intake on the bottom and side of the case and then 3 fans in the top for exhaust. But
differences to your proposed setup might be neglegible. I personally think the differences between companies are not that big. I got one xspc radiator and an alphacool one, but ekwb and hardwarelabs are equally good.