Question H100i doesn't fit my P400A. Did I buy an AIO that doesn't fit my case? :(

Mar 21, 2020
I just bought a Corsair H100i RGB PRO XT. I was installing it into my case (Phanteks P400A) this morning and I realized that the radiator with both fans attached won't fit to the upper grill of the case. Both RAMs are blocking the fans and it doesn't reach the screwing holes up top. That plastic cover on the mobo blocks the fans as well. My mobo: MSI B450M-A PRO MAX.
Here are a couple of photos as well:
One showing which parts block the fan fitted radiator. Radiator does fit without fans but when fans add thickness, those parts block. The other is showing screwing slots up top the case.

Am I doing something wrong or did I waste my money buying a cooler that won't fit my case... That would be sad.

Thanks for help.

have you thought about using it on front as intake but I guess it won't look as good as the rgb fans, you could use the fans as exhausts where that radiator only just fits now.

it fits on front -

I don't have same case but same AIO and it works okay as intake on my case

Last edited:
Mar 21, 2020
Oh, using it at front is an option and I can try it. Maybe I can try keeping the Phanteks RGBs where they are and fit them to the radiator and then use normal Corsairs on top as exhausts. I just can't believe how I bought fans that won't fit my case. Everywhere it is listed as compatible. Do you have any recommendation for another AIO that will hopefully fit my case?
Thanks a lot for the reply.
fans that come with radiators are different to fans that just come with cases

Air flow fans are used for cases, Static Pressure fans are used for AIO. Main difference is where they direct the air and how strongly

you can use AIO fans as air flow but the other way doesn't work as well.

best best is use Corsair fans on AIO and have the Phanteks as exhaust in roof
Mar 21, 2020
Oh, I see. I will be using the Corsairs for the AIO surely. Will the airflow direction change up front? Air will go in to the case from front through radiator (the third front panel fan staying as it is) and then exit from the rear and top exhausts, right? And for the radiator, does it have to be facing front ahead of the fans? I mean, outside > radiator > fans > case.
If that is how it works, I can start reorganizing my case tomorrow.
pretty sure you can fans on front or behind radiator, mine are only internal as you can't see them through mesh on front of case.

the fans work just as well in either location, in pull or push config
obviously if you have them infront of rad you need them in push
Mine are in pull.
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