Top choice for 9900K with AIO cooling is the best thermal paste designed for high temperatures.
Top choice for 9900K with AIO cooling is the best thermal paste designed for high temperatures.
The most effective option would likely be kryonaut, though it comes with a high cost. I switched from kryonaut to noctua NTH1 and didn’t see a significant change.
For affordability, simplicity and consistent performance would recommend this TIM: https://www.newegg.com/arctic-cooling-ac...000S-00016 It functions reliably across all situations I've experienced, even in subzero (LN2) cooling conditions.
I suggest checking all options, Kryonaut should give the coolest temps. The gap between Noctua NT-H1 and Kryonaut is minimal. You might also consider trying the new NT-H2. For your setup, a small dot around the size of a grain of rice works well with NZXT X72 (I use X62).
Similar opinions as others shared. Most pastes will vary slightly, only by a few degrees at most, in terms of performance. What could count is how long it lasts. I've used Mx-4 in several systems for over a year without any problems. I've also changed coolers a couple of times but had to rely on generic paste from local stores, which dried and crumbled within months. Tl;dr - opt for well-known brands. Arctic 5, MX-4, Noctua, Cooler Master, Kryonaut, etc.