Would the l9x65 be a good fit for the case without the fan? It's pretty much a solid wall of heatsink with no air-gap and it still keeps within the keepout zones.
https://noctua.at/en/products/cpu-cooler-retail/nh-l9x65
Also it's 340g with 51mm height with no fan per the spec page:
Height (without fan) 51 mm
Width (without fan) 95 mm
Depth (without fan) 95 mm
Weight (without fan) 340 g
So the specs of the L9x65 look better than it performs. I looked across several reviews and for some reason the L9x65 has middling to poor performance, and Noctua themselves only recommend it for 84W TDP or lower even with their fans.
I made a post on reddit where I list out the dimensions of the compatible passive coolers, and based purely on the numbers and reviews I could find, my estimated performance ranking.
https://www.reddit.com/r/sffpc/comm...00k/ein0qbr?utm_source=share&utm_medium=web2x
One heatsink I haven't added yet is the Big Shuriken 3 since using the Intel bracket apparently allows it to be mounted on AM4 in the correct orientation, and that might perform even better than the Pallas 120.
*EDIT* I found the specs for the Big Shuriken 3, and plugging that in to the chart in the post above, here is my current ranking.
Based on the information available, the best performing heatsinks for passive cooling, keeping in mind the 55.9mm CPU cooler height limit of the SM550/560 should be:
- Raijintek Pallas 120
- Big Shuriken 3 (using intel bracket for proper orientation)
- Thermalright AXP-100 series (difficult to find without Taobao/etc)
- Cooltek CR-701 (also difficult to find)
- Phanteks PH-TC12LS
I've ordered the Pallas 120, Big Shuriken 3, and Phanteks PH-TC12LS and will be putting them head to head in my SM560 once it comes in. My CPU is a non-delidded R5 2400G, and I'll be testing both with stock clocks and CPU+GPU overclocks to push each cooler to the limit. I've also got a digital scale and calipers to do more precise measurements of the dimensions.