Lian Li cases are made of aluminum so they are a lot noisier than those made of steel. I think they all still use 80 mm fans instead of 120 mm, so they generate a lot more noise because they run faster and are less efficient at cooling the system.
75 C is still really high for CPU temperatures. Some graphics-intensive games like WoT really give it a workout, at least if you run it at maximum graphics settings which is where I see 80 C if I play for a while. Anything that gets all 8 hardware threads cooking away at near 100% load is going to generate a lot of heat. Even some video processing apps use all the threads at max cycles and do the same thing.
I am extremely glad that I got a liquid cooling system. It is really no fuss, extra robust with no real chance of springing a leak, and it takes a lot of the heat away from the motherboard area to the top of the case where the radiator and fans are mounted, so the interior around the electronics stays a lot cooler than normal. All the reviewers give it high marks for working far better than a fan and heatsink. It was also quite simple to install. The area around the CPU is also a lot less cluttered.
EDIT: I was going to post a review showing how well it worked compared to other fan/heatsink combinations. But it turns out
the new H80I GT sucks.
This is a real disappointment. The much bigger H110I is still the top performer in this particular test, even in the new "GT" form. The old H80I used to be right below it in the tests. But now it is way down the list. It only works moderately well at the high setting, which is incredibly noisy. You definitely don't want to run it at the high setting. It will drive you nuts.
So I still recommend some sort of liquid cooling system. But the new H80I GT is definitely not it.
Based on these test results, I'd probably even look at a different vendor altogether, like the
Fractal Designs Kelvin S36.
This is an even far better arrangement in the Fractal Design cases because it uses the very top fans instead of the back fan. I may very well get one of these for my own system. Things have progressed a lot in a bit over a year when I built my system. But it does seem the Fractal Designs cooler is a lot noisier than others, so something else entirely may very well be the optimal one.
