Just installed my H115i. Is my mounting procedure and current temp ok?

Full disclosure up front: I'm new to this and I have a terrible case. Masterbox Lite 5 RGB. It looks good but it has bad airflow. I'm paranoid about modding so I'm just going to get a new one when I can and sell this one. Until then, I've had to mount the radiator on this case. Here are the case specs

The case had 3 front stock fans, 120mm. I took them off and fiddled around, reading manuals, looking articles up and asking questions on the forums for around 6 hours yesterday.

End result - I ended up attaching the radiator inside the case on the front panel, while holding the 140mm fans up in front of the case and using the long screws to mount both the radiator and the fans on the mounting bracket.

First of all, was this ^ okay? Because there were smaller screws, and I screwed them in too [radiator was still in the same position, inside, I screwed it in from outside]

Problem with this was I had to install the fans inside, and the PSU / HDD sheathe got in the way for the 2nd 140mm fan, couldn't screw it in. So I decided to keep it outside. My temps without the side panel, front panel on were in the 30s.

These are my temps & speeds using iCUE with all the panels on and after a 10 min test on PUBG and Guild Wars 2. [immediately after closing the games the cooler was still at 45C though]

I'd also like help in understanding the normal ranges for temps under load and on idle. If while gaming my CPU reaches 60s and the cooler is around 40s, is that bad? Thank you.

Fans on the inside or outside, it really doesn't matter from a performance standpoint and case mounting necessities usually trump preference. That said, I am not sure I completely understand what you described above. Do you have 1 fan on each side of the radiator?

Your H115i Temp or coolant temperature is the measure of how much heat in the system. It is second stage of cooling management. The first is the more familiar CPU temperature. That is determined by voltage and CPU physical design. More voltage, more heat, but no matter what to connect to the CPU, the heat created at the pins must pass through through the CPU and then through the cold plate on whatever cooler is mounted. All of this is conductive and there is no setting to alter the rate, other than reducing voltage. The cooler is second stage. It collects the heat from the cold plate and transports it somewhere else (the radiator), where the fans then help disperse it.

The relationship between coolant temperature and CPU temps is this:

a) Coolant temperature is the minimum possible CPU temperature when the Vcore is at 0.0 volts. You won't ever be at 0 volts except when shutdown, so in practical terms you will always see idle CPU temps just a bit above the coolant temp even when using C-states, EIST, and other power saving features. Turn all those off and the difference will increase.

b) +1C coolant temp = +1C CPU temp. Every time you add 1C to the coolant temperature, you raise that basis/lowest possible CPU temp by 1C as well. A typical 100% CPU load for the 8700K is going to be +4-6C, depending on CPU settings. That is not a lot in comparison to the voltage part of the the total CPU temp (typically +30-50C). Fans help reduce coolant temperature, not the +30C from the voltage. So even with maximum fan speed, you likely can only reduce your CPU temp by a few degrees. While this seems detrimental, it is not. An air tower is bound by the same rules, but has a much smaller capacity to hold heat. It will suffer a greater penalty when faced with the same load. In your case, the "penalty" is the coolant temperature rise and that is small.

c) Typically most people see coolant temp rises of +4-6C for CPU only loads or general mixed use. Gaming or other max GPU loads often give the appearance of more. Some people will see as much as +10C while gaming with large watt GPUs, although it has nothing to do with CPU load or efficiency. When you heat up the case with the GPU waste heat, you raise the local environment temperature. Only 3-4C of the gaming temp might be from load. The rest is because you raise the case temp by +6C and that's the final rule....

d) Minimum coolant temperature is case ambient temp in that specific location. Not surprising, you can't make the liquid in the cooler colder than the room or case temp. Most people will see coolant temps of +4-7C above their room temp and pretty much exactly what the local case temp is at the radiator mount location. Some place are worse than others. I think this is where we need to look at things for you.

Now, if you come back and tell me you are some place tropical and the room temp is 30C, then really your aren't really out of the expected zone. However, based on your introductory comments, I suspect we are looking at some case restrictions making the coolant warmer than it otherwise would. That is an actual CPU temp penalty and something we can work on.

1) If you have a dust filter on the front panel (the full screen kind), get it off. If it is just those little screens at the top and bottom of the front panel, don't worry about it. Putting a full screen across your fans or radiator has a large effect. Pulling air in through the top and bottom openings does pose a physical restriction, but not to the same degree.

2) Can you elaborate about the front fan situation? I am not sure I quite understand. Did you mount the H115i behind the existing RGB case fans and then use 1 of the SP140L fans from the kit on the top of the radiator?

3) Slow your H115i fan(s) down. The cooler's default curves assume a 20-23C room/case temp and no other factors. At 39C, it thinks you are under great load (+16C), when in fact this is just the case temp. This is one of many reasons to always use your own custom curves and not the presets. Click the + to create a cooling mode. Set your baseline temp (about 39C) to something much quieter, like 600 rpm. Starting at 42C, slope it up until it reaches 1000 rpm at 45C. 50C=1500. Then 60C=100%. This should give you normal fan levels for your current temp zone. You can run the fans at max, but if the local area is 39C, then that is as low as it goes. Everything on the iCUE screen suggests the case temp is generally about that level.

Coolant temperature should be slow to go up and down. This may be particularly true on the down cycle if your case temp is the limiting factor. If the case temp goes up to 44C in the local area, you can't bring the coolant down below that until the case cools down. Normally, you might see a 2C drop in the moment after closing a game, with the remainder taking several minutes to flush out. Think of the cooler as a waste heat removal device. It takes it from the CPU and holds it until it is able to dump it elsewhere. GW2 is about +4C for me on a 8700K@1.30v and 280mm cooler. That would suggest at least 2-3C of your coolant temp is environmental, but also take the use into consideration. Doing the world boss tour or 20 minutes of the new World Event slideshow is going to heat things up more, even if GW2 is choking on the one core is actually uses.