Traak
2011-10-09, 01:31 AM
I once had a Koolance liquid-cooled tower computer. I had the motherboard chipset, hard disk drives, CPU, and video card all liquid-cooled. It was noisy, but it was a LOT quieter than the air-cooled predecessor was.
I noticed that the temperatures rose steadily over time: cool on startup, but markedly warmer after running a while. This was in an air-conditioned room, which had its temperature stabilized by the A/C.
This told me my radiator was inadequately sized.
If you have a liquid-cooled rig, you can diagnose if you need a bigger radiator by paying attention to the coolant temperatures.
When you first turn your system on, run some macro or repeatable video stress test, that only lasts a few minutes.
The temperatures to measure are:
Room temperature
Coolant temperatures before the radiator, after the radiator, and in the reservoir
CPU temperature
After the system has been running a while, run the same repeatable stress test.
Measure the same temperatures.
If you notice that your room temperature is steady, but your reservoir, CPU, or after-radiator temperatures are higher, then you have a system that is suffering from heat soak.
Your radiator is not removing adequate heat to maximally lower your system's temperatures.
This is easy to fix by just adding a bigger radiator, and a few more fans. Ideally, temperature of coolant exiting the radiator should be close to or at room temperature. This ensures that you have dumped all excess heat from the system, and that your radiator is sized to adequately serve the components you have liquid-cooled.
You don't even have to use some fancy radiator designed for liquid cooling a computer. Go to the junkyard, yank a radiator from a compact car, and adapt it to your system. It ain't rocket science. With a big enough radiator (the closer you can slant it away from vertical and towards completely horizontal, the more easily convection will allow air to pass through the radiator from below and exit from the top. This will allow you to only use fans at whatever level of temperature differential between ambient and coolant output that you want.
To make it more portable, you can add quick-disconnects on the extra radiator that seal both ends upon disconnect.
In fact, you could design a system that used an automotive radiator or two as the primary radiator(s). With enough airflow area and cooling fin area exposed to said airflow, you will not need cooling fans for your radiator. This will further reduce power consumption by the lack of fans needing to be powered.
For the most part, cooling is done with small fans blasting lots of air through small areas at high speed and noise. By using lots of air through a much larger area at very low speed to cool your radiator instead of small amounts of air at high speed, you can drastically cut the noise level, and even have a silent-running PC, if you care to liquid-cool your power supply and only run SSD's.
Another issue I took care of was dust. I didn't like the negative pressure in my case causing dust to leak in at every available joint. I solved this by flipping my cooling fans on my radiator to blow inwards from the top, and each had a fine foam filter on them. The filtered air entered the computer case from the top, and was exhausted by a few fans lower down. This kept case pressure positive, and ensured that the air entering the computer entered it through the filters.
Since my RAM was not liquid-cooled, I found that I could clock it higher if I placed a small 80mm fan blowing directly on it.
Liquid cooling is effective, but to gain maximum efficacy, it has to have coolant that is brought down to just barely above or at ambient temperature. And junkyard radiators are an inexpensive way to do this. If they leak, since this isn't a high-pressure system, you just slather silicone on it, and fix the leak.
I noticed that the temperatures rose steadily over time: cool on startup, but markedly warmer after running a while. This was in an air-conditioned room, which had its temperature stabilized by the A/C.
This told me my radiator was inadequately sized.
If you have a liquid-cooled rig, you can diagnose if you need a bigger radiator by paying attention to the coolant temperatures.
When you first turn your system on, run some macro or repeatable video stress test, that only lasts a few minutes.
The temperatures to measure are:
Room temperature
Coolant temperatures before the radiator, after the radiator, and in the reservoir
CPU temperature
After the system has been running a while, run the same repeatable stress test.
Measure the same temperatures.
If you notice that your room temperature is steady, but your reservoir, CPU, or after-radiator temperatures are higher, then you have a system that is suffering from heat soak.
Your radiator is not removing adequate heat to maximally lower your system's temperatures.
This is easy to fix by just adding a bigger radiator, and a few more fans. Ideally, temperature of coolant exiting the radiator should be close to or at room temperature. This ensures that you have dumped all excess heat from the system, and that your radiator is sized to adequately serve the components you have liquid-cooled.
You don't even have to use some fancy radiator designed for liquid cooling a computer. Go to the junkyard, yank a radiator from a compact car, and adapt it to your system. It ain't rocket science. With a big enough radiator (the closer you can slant it away from vertical and towards completely horizontal, the more easily convection will allow air to pass through the radiator from below and exit from the top. This will allow you to only use fans at whatever level of temperature differential between ambient and coolant output that you want.
To make it more portable, you can add quick-disconnects on the extra radiator that seal both ends upon disconnect.
In fact, you could design a system that used an automotive radiator or two as the primary radiator(s). With enough airflow area and cooling fin area exposed to said airflow, you will not need cooling fans for your radiator. This will further reduce power consumption by the lack of fans needing to be powered.
For the most part, cooling is done with small fans blasting lots of air through small areas at high speed and noise. By using lots of air through a much larger area at very low speed to cool your radiator instead of small amounts of air at high speed, you can drastically cut the noise level, and even have a silent-running PC, if you care to liquid-cool your power supply and only run SSD's.
Another issue I took care of was dust. I didn't like the negative pressure in my case causing dust to leak in at every available joint. I solved this by flipping my cooling fans on my radiator to blow inwards from the top, and each had a fine foam filter on them. The filtered air entered the computer case from the top, and was exhausted by a few fans lower down. This kept case pressure positive, and ensured that the air entering the computer entered it through the filters.
Since my RAM was not liquid-cooled, I found that I could clock it higher if I placed a small 80mm fan blowing directly on it.
Liquid cooling is effective, but to gain maximum efficacy, it has to have coolant that is brought down to just barely above or at ambient temperature. And junkyard radiators are an inexpensive way to do this. If they leak, since this isn't a high-pressure system, you just slather silicone on it, and fix the leak.