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post #1 of (permalink) Old 02-07-2016, 07:23 PM - Thread Starter
CrazyElf
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Why is this thread even needed?
One of my pet peeves in recent years has been the rise of Close Loop Coolers. They have been misleadingly advertised as easy to set up, yet providing performance like water cooling, which most enthusiasts associate as being superior to air cooling.

Custom loops can indeed, when built well, be quite a bit better than air cooling. However, the majority of AIOs, as I will discuss below, are not really an upgrade to air cooling at all. In particular,

I got this inspiration from Shilka, who has done a good job of writing "why you should not buy" certain models of power supplies known to be terrible. I feel like someone needed to write a thread like this.

I suppose I should distinguish between AIO and CLC
  • Closed loop cooler: Pre-filled loop that cannot be opened up or filled by the user.
  • All in one: Typically a custom loop that has been prefilled, but can be refilled and upgraded by the end user. Ships with custom loop parts as well.


I firmly believe that where CPU cooling is concerned, most CLC users would be better off with a dual tower air cooler.


Do air coolers have any drawbacks?
Before I begin, do air coolers have drawbacks? Sure they do. Let's explore.
  • About the only damage that a dual tower in that regard is that it does put a bit more pressure on the motherboard (they can weigh more than 1.5 kg with fans attached). However, the risk of damage to the motherboard is miniscule compared to the risk of a poor quality CLC leaking, which anecdotally at least, seems to happen much more frequently. If you are concerned, you can add support brackets and I would recommend removing a heatsink before moving (same with a water cooling AIO too, as moving it around may increase the risk of leaks).
  • Large dual towers can block the first PCI-E slot. There have been some solutions on the market in an attempt to address this, such as the D15S. For motherboards that have their first PCIe slot a an x1, this is a non-issue.
  • You may also have to make sure that your case has sufficient clearance for the biggest coolers.
  • Tall RAM heatsinks can be blocked (not as big an issue these days as DDR3 and DDR4 do not run hot enough to justify those heatspreaders).

There have been complaints of LGA 1151 CPUs being damaged by poorly built air coolers due to their thinner substrates (only 5 layer PCBs versus 8), but most well built heatsinks will prevent you from applying excessive pressure onto the CPU that exceeds Intel's spec anyways.

A D15S - note the asymmetrical design intended to prevent PCIe slots from being obstructed and the fins on the bottom being cut, which allows for taller RAM.



Those are the main drawbacks to air cooling.

Why not a CLC then?

So if air cooling has its drawbacks, a CLC seem like a great alternative?
  1. Cost
  2. There are more parts to fail
  3. They lose their liquid inside to evaporation over time
  4. The performance to the noise ratio for most CLCs is actually not as good as the top dual tower air coolers
  5. If they leak, the damage can be widespread - also to the rest of your computer parts


Price
As a general rule, the dual 240 CLCs are more expensive than a high end air cooler.

Currently, the top end coolers can be had for well under $100 USD. My current cooler, the Cryorig R1 Ultimate, can be had for $80 USD when it goes on sale. Prices will vary nation by nation, but in general, a 240 CLC will cost more than a dual tower CPU cooler.

The bottom line though is that there is an opportunity cost to be had there. Whenever you spend money on one part, it has to be taken out elsewhere.



More Parts to fail




Very simply put, in an air tower, about the only thing that could fail is one of the fans. Typically many dual tower CPU coolers have a pair of fans, which somewhat mitigates this.

However, on a CLC, you have all of the parts in a water cooled system that can fail, only often lower quality.
  1. Fans (like in an air cooled tower)
  2. Pump
  3. Galvanic corrosion over time on the parts
  4. Leaks are a concern too (will describe in a separate section below)

Fans need no further explanation. That said, ideally you'll want 2-ball or FDB bearing fans to last as long as possible.

The pump is a problem because CLCs typically do not ship with good quality pumps. Generally in a custom loop, pumps like the Liang D5 are known for their reliability and have enough pressure to sustain a pretty decent sized loop. The majority of CLCs do not have good quality pumps and this is a point of failure.

Galvanic corrosion is also an issue because most CLCs ship with aluminum radiators (rather than copper). You get a mixing of aluminum, with other metals - most notably copper, nickel, and brass (technically an alloy, not a metal). That over time creates galvanic corrosion and can be an issue. CLC vendors usually know this and add ethylene glycol or some other anticorrosive to slow this process down (but it is physically not possible of course to stop it).



This image is from a custom loop, but I expect that a CLC will do worse, because most custom loop builders will not be mixing aluminum with copper/brass/nickel, and they will be changing their water annually.


They only last for a few years as liquid is lost to evaporation
A typical CLC, being non-refillable is only going to last for a few years. The reason is because tubing is permeable. Custom loops suffer from this flaw too and have to be "topped up" every now and then as well. Water levels drop in the reservoir.

Again, most CLC vendors know this. A good CLC will use Tygon Norprene or something similar to mitigate this. Norprene (which is used in the automotive industry for brake and fuel lines) has a much lower Water Vapour Transmission Rate (WVTR) and as a result will not require topping up nearly as often. This will mitigate, but not eliminate the problem.

Combine that with galvanic corrosion and you get something that will not last more than a couple of years. Eventually too little water will be in the system and the pump will run dry, choking on air.




If they leak, the damage can be widespread - also to the rest of your computer parts
Like in any water cooling system, there is the risk of leaks. However, just like how the pumps are not well built, there is the risk of leaks. You aren't getting top quality fittings, and unless Tygon Norprene or something of similar quality is used, you are probably not getting good quality tubing either.

When a CLC leaks, it is not just the CLC that is in danger; it is like any other water cooled system leaking. It can short circuit your CPU, motherboard, GPU, RAM, or perhaps power supply.

Depending on the manufacturer, they may compensate you for damages::
http://forums.bit-tech.net/showthread.php?t=233533

Now it is true that the user above should have recognized the warning signs and taken the CLC out, but the fact remains that the CLC damaged his components and he did not receive compensation.

If you must buy a CLC, make sure that you buy from a company that has been known to honor the costs of the rest of the PC. Amongst the companies I've seen making CLCs, Corsair seems to be one of the few that does, so if you are not convinced by this thread, you may want to consider a Corsair part.




The performance of most CLCs is actually not as good as it seems
If you look on the Internet, you'll find a lot of reviews and typically, you'll find the the 240 or 280 CLCs outperforming the towers by a couple of degrees. The problem is that they are doing so on the basis of faster fans. The most important metric is actually performance to noise ratio. There, the top air coolers have been surprisingly competitive.

See here:
http://www.tweaktown.com/reviews/6313/noctua-nh-d15-cpu-cooler-review/index.html



What this image is telling me is that the D15 is performing almost as well as the top CLCs, but is a lot quieter. Were you to put 2500 rpm fans on the D15, it would outperform every CLC shown here.


I should mention that there have been a few decent high end CLCs: The Corsair H110i GTX seems pretty decent (Click to show)

http://www.tweaktown.com/reviews/7320/corsair-hydro-h110i-gtx-high-performance-liquid-cpu-cooler-review/index5.html



However, I still recommend getting an open loop AIO cooler. Keep in mind the H110i GTX is one of the most expensive CLCs out there.

The thing you have to consider though is, given that most CLCs do not perform well against competing dual towers, have the increased risks of failure, the danger of leaks associated with a custom loop (only on lower quality parts), is it really worth it?


Are there any exceptions?
The kits made by Swiftech and EK are pretty good. These are AIO kits. These do offer a better performance to noise ratio than any competing solutions from dual tower air coolers and for that reason I have no hesitation in recommending them.

The Swiftech H320 x2


These AIO kits, although they cost more, mitigate the majority of the flaws that CLCs have:
  • They can be refilled so loss of liquid is not as big an issue.
  • They have high quality pumps (actually pumps that belong in a custom loop), which means that they are expandable and that risk of pump failure is much lower.
  • They actually perform quite well compared to air cooling dual towers (actually even better from a performance to noise standpoint)



The only drawback would be that they can still leak, which is the risk of any custom loop.



Conclusions
The point I want to make is that a CLC is not worth it. Not given the massive drawbacks they have over a dual tower. Basically, your options should be the following.

From cheapest to most costly:
  1. Cheap budget air cooler
  2. Higher end dual tower CPU air cooler
  3. Expandable AIO (ex: Swiftech and EK make these)
  4. Full scale custom loop
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