Best 140mm height CPU cooler?

[_tempted_]

I’m looking building another ITX system as a server. I really like my Thermaltake V1 ITX case since it fits nicely in my IKEA book case. I would like to buy another one for the server. The CPU cooler height limit is 140mm.
 

I’m having trouble finding a cooler that I think is strong enough. There are times when I will have this server running with a full load for an extended period of time. I like Noctua and am “hoping” the NH-U9S is sufficient but don’t really think it is. The case supports AIOs with 120 or 140mm single fan radiators but I’d not find 140mm AIOs at Newegg. Are 120s good enough to keep a 5950x cool at full load?
 

Also I’m not married to the V1 case necessarily but I like the idea of a cube case that will fit with a 13x13 bookshelf space with some breathing room on all sides. Also… this server does not need disk space as I have a NAS. 
 

Thanks!

[Dogzilla07]

Thermalright Silver Soul 135

 

But, this is only if you've got the plexiglass panel on the top, if you swap the panels around, and you put the perforated panel on the top, then you can do pancake, top down cooler, and your best option becomes Be Quiet! Dark Rock TF2, or Noctua NH-C14S (with it's fan below, and a slim one on top).

 

If u don't mind switching to SFX power supply, don't have hard-drives and not too many SSD, and a <275mm , 2 slot card u can downsize from your (22L case), to Silverstone Sugo 16 (13L case). It supports even taller coolers.

[WoodenMarker]

The NH-U9S should be fine but a 120mm AIO can perform better. 

Where are you shopping / located? Budget? What are you looking for in a cooler?

[Demonic Donut]

I agree on the C14 and it will perform better than a u9s. I have one on my wife's 3600 and it runs very cool with the 140mm fan mounted below the cooler and a side panel fan blowing into it.