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Old 09-03-2016, 06:08 PM
c-attack c-attack is offline
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There is no specific danger or fail temperature for any Corsair cooler. The rubber and other materials can handle exceptionally high temperatures, well beyond anything you could ever create in a computer case. Adhesives and other chemical additives likely do not benefit from extended water temperatures close to boiling, but by that point your computer is ready to shutdown anyway.

Your end CPU temperature will be the limiting factor. The water temperature is effectively your base minimum CPU temperature. Just as an air cooled CPU cannot be below the air temperature inside the case, you cannot have CPU core temps below the water temperature. The water system has the advantage of being able to hold more heat at one moment.

So, your effective equation is: water temperature + voltage induced temperature = Final CPU core temperature. That voltage load is constantly changing, but I will used a fixed 100% load for the explanation. If you run a stress test and your starting water temp is 30C + voltage load = 70C core temperature, than 40C of that is from the voltage level. Of course reducing the voltage will reduce the temperatures, but the CPU does this on its own under most circumstances and it is not something you have active control over. If I re-run the stress test at 35C water temp, the result will be ~75C core temperature. At 40C water temp, 80C core temp.

The transfer rate of heat through the CPU/lid/TIM/cold plate is essentially constant and not something you can control. The heat will go through and into the water stream as fast as the materials will allow. That rate is more or less the same on most commercial products. The variable you can control is water temperature and the fans help remove heat from the water. Pump speed determines how many trips from the cold plate to radiator and back each unit of water can make per interval of time. However, flow rate is not usually an influential factor on large all-in-one coolers like the H115i. You can use the Quiet mode without sacrificing performance, but I would encourage you to experiment for yourself. Every case provides a different environment. To that same end, I would try with the top cover on and off to see if the cooling benefit is worth any increase in noise.

If your starting water temperature (at warm idle) was 32C before gaming and 40C during the gaming, the most you could possible reduce the CPU core temps at any fan speed is 8C, by bringing the water temp back to 32C. In reality, that is never possible. From what I can see in your videos, it looks like 800 rpm vs ~1700 rpm on reduced the water temp by 2C. I know I would not take the level of noise for a 2C reduction in core temps. The "40C=100% line" is based on a room/case temperature of 20-23C. It takes a very specific amount of energy to raise that volume of water from 23 to 40C. That would be quite a load and you would want 100% fan speed. The problem is when your room or case environment is more 23C. If you were in the Tropics and it was 35C in your room, your case temps would be 40C at idle with minimal voltage load. You don't need 100% fan speed at idle and the core temps would hover around 40C regardless of fan speed. This is why you should use custom or fixed fan profiles in Summer.

Aside, from all of that, if the cooler is still doing strange things with the fans in default profiles, there is some sort of software/firmware problem. The fixed fan speeds may be a solution, but I don't know if custom curves will work in this state.

Last edited by c-attack; 09-03-2016 at 06:10 PM.
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