Which cooler to choose for AM4: Noctua NH-L9i or L9a?

[Mortis Angelus]

In the past it was easy. If you used Intel CPUs/Sockets, you chose the NH-L9i. If you had AMD, you chose the L9a.

 

But now Noctua confuses me, with their upgrade package: http://noctua.at/en/noctua-offers-free-am4-upgrade-kit-for-nh-l9a-and-nh-l9i-low-profile-coolers

 

It seems like it suddenly is possible to mount either a L9i OR L9a onto AM4 with this new bracket. First of all I don't understand how that is possible. Second of all, if I own neither of the coolers at the moment, which one should I go for?

 

Will the new AM4-bracket make the cooler taller than before?

 

Planning on using an NH-L9x with AM4 ITX-mobo in a case with about 4 cm clearance.

[ravenshrike]

Because you remove the original mounting feet from the cooler and replace them with AM4 mounts. Other than the feet, the coolers are the same.

 

Also, while it might be a few millimeters taller, it's not anywhere near 4 cm.

[oriol]

The NH-L9a comes with AM3/AM2/FM1/FM2 mounts, the NH-L9i comes with LGA115x mounts. You can replace either of them with the new AM4 mounts contained in the NM-AM-L9aL9i kit.

 

The coolers are NOT identical though, just check the measurements: The NH-L9i is square whereas the NH-L9a is rectangular (slightly less wide but longer). They are tailored to fit the respective keep-out zones. Overall, the NH-L9a is slightly bigger and heavier, so it also provides slightly better performance on AM4. Therefore go with the NH-L9a if you own neither of the coolers yet!

 

The brackets don't increase the height of the cooler at all. If you have 40mm of cooler clearance, it will work.

 

The reason why the NH-L9i can be fit to AM4 whereas it couldn't be fit to AM3/AM2/FM1/FM2 is because the keep-out zone is wider on AM4.