So looking at what everyone said, we have the slim SilverStone for max clearance and that really important point about tubing durability. Basically youre balancing thickness vs cooling capacity vs long term reliability. The 13600K gets surprisingly hot so if you can fit a standard 27mm thick radiator instead of a slim one, you definitely should. Market-wise, the Fractal Design Lumen S24 v2 is one of the most practical picks for ITX right now. The big win there is the pump being integrated into the radiator. It lets the CPU block stay tiny which helps with RAM clearance, and it completely solves the issue of air bubbles getting trapped in the pump if you have to mount the rad in a weird orientation. If you want something more modern with a focus on noise levels, the Cooler Master MasterLiquid 240 Atmos has been getting great reviews for its pump efficiency. Comparing them:

• Fractal Lumen: Best for tight block clearance and flexible mounting.
• Cooler Master Atmos: Better noise-to-performance ratio for the 13000 series chips.
• SilverStone VIDA: Still the king if you literally only have 38mm of total space. Tbh just make sure whatever you pick has those rotatable 90-degree fittings at the block. Without those, youre gonna have a bad time trying to close your side panel.

Noted!

^ This. Also, really glad someone brought up the tubing durability. Looking at the thread so far, it seems like the choice really boils down to whether you prioritize that extra clearance or go for a thicker rad for better thermals. I remember my first real dive into SFF builds a while back. I was so obsessed with getting the thinnest parts possible that I didnt realize how much I was sacrificing in terms of noise. The slim fans I used in my old setup were honestly pretty loud because they had to work twice as hard to push air through. I ended up having to undervolt my CPU just to keep the temps reasonable because it was basically a space heater in a shoebox. Just be careful when youre actually fitting everything in. I've seen people accidentally kink their tubes trying to close the case, which is a recipe for disaster later on. I would suggest making sure you have at least a little bit of wiggle room for the cables too. My current setup was a total pain to cable manage because the block blocked half the headers on the top of the board. Definitely take your time with the dry fit before you go tightening everything down... it'll save you a lot of frustration.

Late to the party but this whole thread is 💯. Glad I found it.

Saw this earlier and wanted to weigh in. I totally agree that the SilverStone is a solid choice for clearance, but as an expert who has seen way too many AIOs fail in cramped ITX cases, I really have to emphasize reliability and long-term safety. When ur working in SFF, those tight tube bends can actually increase the rate of permeation over time. I mean, basically, the liquid slowly evaporates through the rubber because of the high internal heat and physical tension. You really want to look for EPDM rubber tubing and a pump with a high MTBF rating. If the pump dies in an ITX rig, its a total pain to disassemble the whole thing to fix it. Tbh, if you have the clearance for a standard 27mm radiator, I would check these out:

• NZXT Kraken 240
• Phanteks Glacier One 240MP The Kraken uses a 7th gen Asetek pump which is the industry standard for reliability!!! Also, please watch ur pump orientation. In SFF builds, its super easy to accidentally make the pump the highest point in the loop, which traps air bubbles and destroys the bearings. Just stay cautious with the cable and tube routing and you should be good.

For your ITX build with an i5-13600K, the SilverStone VIDA 240 Slim AIO is an excellent choice. It features a 22mm-thick radiator and 16mm-thick fans, totaling 38mm, ensuring compatibility in space-constrained cases. The integrated pump within the radiator reduces noise and allows for a slim CPU block, minimizing clearance issues with RAM. This cooler effectively handles the i5-13600K's thermal demands without compromising your SFF build.