1400rpm seems a little low for a Corsair 120mm like the h55. They usually run around 2000rpm.
Youll have to look to see where the pump 3pin is installed. It's probably either cpu_aux or a sys_fan header. And that can be an issue only because that header is not tied to the gpu. So when the gpu heats up, the motherboard isn't, so fan speeds aren't changing much at all, and temps go up.
Also verify that in bios, that particular header has qfan or other controls disabled, and header duty cycle is permanently set to 100%.
If your bios allows, the header for the rad fan should be set for gpu temp, not auto or system or cpu etc. If you can't, you'll need to use SpeedFan, in which it does allow specific headers to be retasked for a different address, you'd retask the header for gpu. And that's after watching several tutorials about how to figure that program out and set fan curves.
Many install videos will only show you how to install things, they'll not actually show you anything on how to set it up and use it, if it's different from theirs. Otherwise those videos could stretch hours long.