Water Cooling: Thoughts After 2+ Years

Craig Prall

An Experiment In Progress

In the early fall of 2019, I decided to build a gaming computer using water cooling which is still my current build. Normally, I would be seriously thinking about an upgrade of some sort after this long. I would start by upgrading the GPU and later the CPU/motherboard/memory because usually, the GPU shows its age first. However, thanks to the pandemic, there is no better graphics card: 

  1. That is available to be purchased ...
  2. That also costs less than what I would normally spend on an entire system

I am in the (bottomless?) EVGA queue for the EVGA GeForce RTX 3080 FTW3 Ultra Hydro Copper. That would be a direct replacement for the 2080 Super FTW3 Hydro Copper I have now. Interestingly, I was moved from the non-LHR (not a Low Hash Rate card - part number 10G-P5-3899-KR) queue to the LHR queue (part number 10G-P5-3899-KL) by EVGA with the explanation that they aren't sure the non-LHR version will ever be made. Still haven't gotten a chance to get one, though.

So, I've had this system - my first water-cooled system - for over two years now and have some thoughts about the experience.

You Should Like to Do Maintenance

Even if nothing changes on the system, water-cooling manufacturers recommend draining, flushing, and refilling the system with new coolant every 6-9 months or so. I have done it about four times in two-plus years. Originally, I was using Primo Chill's PC Ice, UV Blue. The odd thing about that coolant is that, over time, it lost its coloring until it was nearly clear. I'm still trying to figure out where it went. It wasn't stuck on the tubing, stuck in the CPU block, GPU block, etc. It seemed just to turn clear. I switched to EKWB EK-CryoFuel, Navy Blue, and it seems to hold its color. I'm on my second third batch now. Both of those are translucent rather than what's known as "solid" colors. That is, they are mostly clear-colored water where the solid fuel is pigmented and has a bad reputation for gunking up the fins of the blocks.

Changing the coolant, in my case, is a minimum of a few hours of work. The general steps are:

  1. Take off the tempered glass front, top, and side panels to reduce the system's weight
  2. Take the system off the wall (and it still weighs about 40 pounds or so)
  3. Remove the wall-mounting bracket and put the feet on the bottom of the case
  4. Drain the coolant by hooking a hose to the drain valve
    • Wrangle the system in all directions, including upside down, to get as much fluid out of the nooks and crannies as possible.
  5. Remove the back of the case and hook up an external power supply unit to the water pump
  6. Fill up the system with plain distilled water
    • Fill up the reservoir
    • Run the pump using the external PSU with a jumper switch to almost drain the reservoir (while being very careful not to "dry run" the pump)
    • Repeat until the system is full
  7. Run the distilled water for an hour or so, refilling as necessary
  8. Drain the distilled water (again with much wrangling)
  9. Fill up the system with fresh coolant (see step 6)
  10. Run the system with the new coolant for about an hour to get the air bubbles out of the system and refill as necessary
  11. Remove the external PSU, reconnect the system PSU, and test
  12. Put on the back of the case, reinstall the mounting bracket, and remove the feet
  13. Put the case back on the wall
  14. Reinstall the front, top, and side tempered glass

I'm getting pretty good at it.

Expect to Pay More

The CPU water block adds an extra $100-200, the GPU block is another $150-200, the pump and reservoir are around $200, the radiator is about $100, and then there are the fittings. You should expect to add $200 for those for even the simplest of loops. More if the loop gets complicated and uses a lot of them. The cheapest part is the actual tubing itself. So just going water-cooled added over $1K to the cost of my system, and I have about the simplest single loop possible; it connects the pump to GPU, to the CPU, to the radiator, and back to the pump.

What is the Upside?

There must be some pluses to this, right? There are.

Temperature

This is the reason that people build a water-cooled system. Even when running under the heaviest load, water-cooler builds don't heat up to nearly the same temperatures as a similarly equipped air-cooled one does. In my system, the most demanding games get the CPU up to the 46-49°C range and the GPU to the 54-57°C range. The water temperature is in the high 30°C range and 40°C if I run the system when the room is warm in the summer. While this is an upside for the system, it's a downside for the room the system is in (and the people in that room). The heat that the radiator offloads is dumped into the room. In my case, the system is in a room that is 10'6" x 13' or ~ 136 sq. ft. The temperature rises about 1°F (not °C) per 1-2 hours. In the winter, this is a welcome thing. In the summer .. not so much.

Noise

I expected the system to run cool, but I was surprised at how quiet it runs. At idle temperatures, the system is nearly silent. Even when under heavy load, the system is barely louder than a whisper. A quiet water pump and good fans (explicitly made for cooling a radiator) help a lot here. The PSU fan almost never runs. I have a couple of fans mounted mid-case that blow over the motherboard and out the back, but they are running at a fairly low speed. I added those to cool off the M.2 SSDs mounted on the motherboard.

Endless Tinkering

In addition to changing the coolant, I've made a few changes to the system because .. of course, I did. This isn't unique to this system. It is the case with nearly every system I have built. I can't help myself.

One of the more involved changes I made was to swap out the CPU (only) water block for a combo CPU and VRM cooler with a flow indicator, which is generally called a "monoblock." I went with the Bitspower Mono Block for ASUS ROG Crosshair VIII Hero. I like the fact it cools the VRMs as well as the CPU. The flow indicator is also a very welcome addition in that shows that the coolant is circulating. This one is not "active" in the sense that it does not have a flow sensor that connects to the motherboard. It only visually shows that the fluid is flowing. At some point, I may add an active inline flow/temperature sensor that does report flow to the motherboard.

I also added a small LCD screen that monitors various temperatures and voltages (via AIDA64). That turned out to be more of a project than I would have guessed. I bought a "high-res" 720p 5" monitor panel. AIDA64 has some built-in gauges that were made for lower-resolution displays, so those were very tiny on an already tiny display. AIDA64 allows for custom gauges (as a series of images representing the gauge at various levels from 0 to 100%). I drew those using GIMP, which was a new program to me.

Lastly, I added a temperature sensor in the loop using a Bitspower G1/4" Temperature Sensor Stop Fitting. This connects to the temperature sensor input on the motherboard and lets me monitor the water's actual temperature. This is something I should have had from day one, and I would say it's not an option for water-cooled systems. It was also pretty cheap.

Other minor additions included adding a second motherboard fan and adding some more memory.

Would (Will) I Do Water Cooling in My Next Build?

I'm honestly still internally debating this. The cost of going with water cooling is pretty steep. It's really a minimum of about $1000 for the simplest loop. The maintenance is more than what air-cooled systems require, although it's not that bad. On the other hand, I really like the unique look, the low temperatures, and the quiet running. I have not had any serious problems with the system as far as leaks and the like. I chalk that up to having bought good quality parts - especially the pump and fittings.

One thing that I realized is that it would be hard to hand this system over to a family member or friend. When I do an upgrade or two, I usually end up with parts that I can use to upgrade someone else's system or make a whole system and give it away. The required maintenance with water cooling is something that most people I would gift such a system to would not (could not) be able to do, so I would want to switch over to using air cooling. That's not difficult in the case of the motherboard. I would have to remount the VRM heatsinks and buy an appropriate CPU cooler. The GPU I have, however, arrived as a water-cooled part, and I don't have the air-cooling shroud, heat sink, and fan assembly. I would have to try to find a third-party air cooler or buy a broken card on eBay.

So the answer at the moment is I really don't know. I'm leaning toward not doing it again or maybe using an AIO for the CPU, which I have done before. I could get a second one for the GPU (which tends to be the hottest component), but then all I have done is an unsophisticated version of the open-loop system.