[SOLVED] Is this normal for a 240mm radiator?

[stanley88845]

I have a Corsair H100i GTX that is around 5 years old and I recently overclocked by i5 8600k to 5ghz at 1.4 volts with a medium level of LLC (droops down to around 1.39 volts under load). Under load however, it'll start off at around 80°c with the fan speeds at 1300rpm in a pretty high airflow case, which isn't too bad considering the fact it has 2 and a half year old liquid metal being used on it right now (as I am testing to see how long liquid metal can truly last before it needs to be replaced) but the liquid temperature equalizes at around 50°c and my cpu temps hover at around 90-100°c at this point with fan speeds at 1300-1600rpm.

While this is all within spec and there is no thermal throttling, I can't push 5.1ghz as it becomes unstable from how hot it is. While I am planning on upgrading my cooler soon to a 420mm aio (the Arctic Liquid Freezer II) I wanted to make sure this is normal before I sell it to one of my friends.

 

[BogdanH]

I'm sure you probably know the answer.. 240mm AIO cooler is considered as minimum (acceptable) for normal CPU load.
For "normal" overclocked 8600K, a 360mm AIO should be enough I think.

 

[stanley88845]

240mm AIO cooler is considered as minimum (acceptable) for normal CPU load.

Ok thankyou so much, this has just made me certain that my aio is fine. Thanks for the help!

 

[rubix_1011]

Consider the following (all AIOs defined in example below have a thickness of 30mm)

A 360mm AIO will have a volume of approx 1,296,000 mm^3
A 280mm AIO will have a volume of approx 1,176,000 mm^3 (~91% total volume of a 360)
A 240mm AIO will have a volume of approx 864,000 mm^3 (~67% total volume of a 360)
A 120mm AIO will have a volume of approx 432,000 mm^3 (~34% total volume of a 360)

Liquid cooling and the capacity it has for thermal removal from the cooling system itself (tubing, radiator, pump, coolant) is HIGHLY dependent upon the following things:

1. total volume of radiator
2. total volume of airflow through the radiator
3. total volume of coolant flow per minute
4. thermal conductivity of the block (contact with the CPU IHS to remove heat)
5. thermal conductivity of the radiator to dissipate heat with the ambient air

Many AIOs use a copper or nickel plated copper base which contacts the CPU. However, most AIOs also use aluminum radiators.

Thermal conductivity
Aluminum - 237 (W/m K)
Copper - 413 (W/m K)

source: https://www.engineeringtoolbox.com/thermal-conductivity-metals-d_858.html

Copper has the ability to absorb and dissipate thermal energy must faster than aluminum, but copper costs much more . This is also one reason why good custom watercooling radiators are made from brass or copper while AIO radiators are made from aluminum (primarily, cost). Copper also costs more than aluminum.