Which GPU exactly are you planning to get?
As for CPU cooling I suggest air cooling over water unless you go custom loop and that's more than your budget. There are all kinds of top coolers available. Just need to keep the height below 160mm. What RAM are you using? Need to know how tall it is above motherboard to make sure cooler and front fan will clear. Take a look on Amazon and Newegg at coolers in the $70-90.00 range. That's where most of the best are unless you find a deal. Some I would consider are DeepCool Assassin, Noctua NH-D14, Zalman CNPS11X Extreme, Silverstone HE01, Gelid Solutions Black Edition...
Sounds like we have more to cooling to do than just CPU. Modern GPU's make 2-3 times as much heat as CPU... We need to be sure the case is cooling properly with the components you have or will have.
Getting case setup and cooling properly is the hardest and most time consuming part of a build... And the most neglected by most builders.
Putting fans in case as intake and/or exhaust is only the first step. These fans only move air in and out of case.
This does not mean heated air is not mixing with cool air.
Nor does it mean cool air is going to where it is needed.
Getting the air to flow inside of case properly is even more important. We want cool intake air flowing to components and heated air from components flowing out of case without mixing with the cool air and warming it up.
How we manage that is what determines where the air flows inside the case. We can do this several ways; deflectors, cooler intake fans, exhaust fans, removing vent grills, using fans with higher pressure/airflow, building ducts to or from CPU/GPU cooler, etc.
Using a remote temperature sensor to monitor what air temps are is the key to finding out where the cool air is flowing and knowing heated air is not mixing into it. By monitoring this we can than make changes to get airflow the way we want it.
I monitor the temps with a cheap indoor/outdoor wired remote or terrarium digital thermometer. Twist a piece of stiff insulated wire into the last 8" of sensor lead so you can bend it to position sensor where you want it... like 40mm in front of your GPU cooler/radiator intake.. to see what the air temp going into CPU / GPU cooler is compared to room temp. The closer it is to room temp the better.. Shouldn't be more 5c maximum, 2-3c is what I usually end up with after 30 minutes full load on both CPU and GPU.
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