Watercooling upgrade

[badb0y]

I think I am going to grab another 7970 and run crossfire in my loop so I need some advice. Right now I have a EX240 and EX120 cooling my 7970 and CPU and the temperatures are pretty good but I don't think my loop can handle crossfire. So I am buying a Monsta 360mm and a UT60 240mm to upgrade my loop would it be enough to handle 2x 7970s at max clocks (going for 1200 core clock) and my CPU at 4.6 Ghz?

Thanks.

EDIT: Update!
The 7970 is gone! (It will be missed)
GTX 780 is my card now until Maxwell/_(?)__ Islands.

I got a good deal on the GTX 780 and jumped on it but now my cooling is as insufficient as it's ever been. Having my GTX 780 overclocked to 1200 Mhz and running Valley for an hour had my CPU temperatures in the 70s(!) and the GPU was also hanging around the 70s(!) and this is on water cooling. I want to keep my CPU and GPU temperatures below 60 degrees Celsius, would that be doable with the originally proposed parts?

 

[Tweakin]

I know some use the 120 mm per 100 watts of thermal as a guideline, but it also depends on the fans / shrouds you will be running. I would think just adding the 360 would be more than sufficient for your needs, but again, what thermals are you willing to accept and how loud will you allow your fans to be.

 

[badb0y]

I know some use the 120 mm per 100 watts of thermal as a guideline, but it also depends on the fans / shrouds you will be running. I would think just adding the 360 would be more than sufficient for your needs, but again, what thermals are you willing to accept and how loud will you allow your fans to be.

Right now I have some Noctua fans but I want to swap them with AP-14s. Also I am not adding these rads to the existing loop, I am replacing my old rads with the new ones. I would be happy with temps below 60 Celsius under full load for CPU and the GPUs.

 

[Tweakin]

Right now I have some Noctua fans but I want to swap them with AP-14s. Also I am not adding these rads to the existing loop, I am replacing my old rads with the new ones. I would be happy with temps below 60 Celsius under full load for CPU and the GPUs.

As long as your pump can handle the extra load, I think you will be fine...that's a lot of capacity for what your running.

 

[Ninhalem]

Adding both of those radiators to your loop is frankly overkill. I've also seen 120 mm of rad space per component plus 120 mm for head room as a good metric.

Also you will need to invest in GT's sooner rather than later given that it appears Scythe and Nidec have discontinued their relationship.

 

[Biggu]

Adding both of those radiators to your loop is frankly overkill. I've also seen 120 mm of rad space per component plus 120 mm for head room as a good metric.

Also you will need to invest in GT's sooner rather than later given that it appears Scythe and Nidec have discontinued their relationship.

this is what ive always heard and used. 120mm per component. It really doesn't matter how thick the rad is. A thicker rad may help but what helps the most is a proper fan setup to rad fin design.

 

[smackababy]

Those two post previous to mine should be ignored. 120mm per component is a terrible idea. A 7970 has a TDP of 300w, which means at peak, you are putting out 300w of heat that has to be dispersed. A 120mm radiator with an 800RPM fan will disperse around 125w at a 10C delta (which is ideal).

Currently, you're about at the edge of where you want to be. Upgrading both by 120m (a 240 and a 360) should cover you, but you might hit higher deltas unless you have higher speed fans. You're adding a 300w part to your loop and only adding about 250w of cooling capacity.

 

[Ninhalem]

I said 120 mm per component plus 120 mm for head room as a starting point or rule of thumb. If you're going to say my information is wrong, then I suggest you tell that to all the people in the water cooling section on OCN since that's where I get a lot of my information on how much rad space I need.

As for fan and radiator configuration, here is some information from a recent thread on OCN concerning push/pull:

CFM is just the value of airflow. The value for static pressure is mmH2O. The higher the static pressure the better. Static pressure is more important than CFM when it comes to radiator fans.

Push is better with high RPM fans(>2000 RPM)
Pull is better for low RPM fans(<1000 RPM)
Doesn't really matter with mid-RPM fans

I usually prefer pull in any situation because it makes cleaning dust of the rads easier. And you really don't see too much of a temp difference with push vs pull. Both Push and Pull at the same times is definitely the best of space allows though.

I vote push-pull over just push or just pull. The difference between push or pull is negligible. Push-pull will net you ~20% to 30% better cooling.

If there's not enough room for push-pull, make room - go with a thinner rad if you have to, and if that won't work then buy a bigger case.

Well, after Martin's first testing done on a single rad which showed that shrouds can increase cooling performance, shrouds became pretty popular with watercoolers. Martin then did a followup test later on which showed varying results depending on which rad was being used. Some rads using a shroud will have worse performance than no shroud. The use of shrouds has dwindled a lot since then.

Some use a 120-to-140 adapter, which is a type of shroud which allows using a 120mm fan on a 140mm rad (since there's still yet to be any 140mm fans that can match the balance of static pressure/cfm/noise on a rad that some of the 120mm fans have).

Some still swear there's a benefit to using a shroud because it allows more airflow to even out and make use of the 'dead zone' behind the fan motor, which is somewhat true, but a lot of fans focus most of their airflow either to the outer edge of the fan or towards the center, so adding a shroud sometimes doesn't allow airflow to even out at all, but instead only gives it more space to concentrate airflow more towards the outside/inside than if there was no shroud. Very few fans have an even distribution of airflow, and those that do, like the Silverstone Air Penetrator, do so by incorporating a crazy style baffle/grill that actually impedes airflow somewhat and makes them have very poor performance on a rad.

Most rad designs these days have what is basically a small built-in shroud that separates the fan blades from the rad fins by ~7mm or so anyway. Bottom line is adding a shroud may or may not boost performance, but definitely will impede into what is usually precious space from your build. My thinking's been pretty much like this, if you have room for a shroud, you'd probably be better off to go with a thicker rad instead.

TFC Shrouds and shrouds in general - Always provide a good performance benefit and reduce noise at the same time. Highly recommended in all radiator setups particularly for higher speed fans unless the space does not make them an option. You can see as much as 10-16% gains on higher speed 38mm fans and 6% gains with slow speed fans. Generally the higher the fan speed and the larger the fan hub, the more gain you will see with shrouds. Optimal depth appears to be somewhere around 30mm +-, this is likely to depend on hub diameter and RPM to some extent.

Push Vs Pull - This depends on fan speed/power. The high speed fans at 2000RPM with a 38mm fan thickness provided the best performance in a push condition. The slow speed fans with 1350RPM with a 25mm fan thickness provided the best performance in a pull condition. I would estimate that performance line is likely to cross in the 1500-1700RPM range where they are equal. So.... slow speed = pull, high speed = push, medium speed = it doesn't really matter.

2 fans Push/Pull vs others - It was very clear that when using two fans per radiator section, that the radiator intself acts as a flow spreader and provided great benefit to straightening out the air for the second fan in a push/pull configuration. Just like doubling up with a pump, there is a pressure benefit to doubling up on fans and this translates to about a 20-30% performance gain. The added fan pressure simply means and added gain in air flow and corresponding performance. None of the experimental pull/pull or push/push configurations provided any noteworthy benefit as it seams the air is simply too disturbed from the first fan to allow the second to perform properly when air is moving. I would always recommend a push/pull configuration for two fans and add a shroud to both sides if space allows.

I hope that is enough information in one place.

 

[BrightCandle]

You are wrong. The basic physics are that all heat input into them loop needs to be dissipated by the radiators. The idea that 120mm per component completely ignores the actual thermal characteristics of the components themselves.

A CPU will take 120W to maybe 200W over clocked.
A high end GPU can be >300W
A memory module is 10W
A chip set might be 20W
These do not all require 120mm of radiator each and for some of them 1+1 is insufficient cooling. It also ignores the fan speed and noise produced.

A Thermochill pa series 120.1 radiator at temperature +10c over ambient with an AR15 at 800rpm and 130W heat source will maintain the water temperature of 10C. Thus it is capable of cooling130W to 10C. Assuming 10C is sufficient (it is for all components) then this will work. That is how the basic calculation works and you can check the 130W @ in reviews.

But your method has no such simple physics based calculation. You have relied on expert reference to OCN, but you yourself can't explain why it works. I can categorically state it doesn't, its bad physics.

 

[Ninhalem]

There's no point in arguing over something that many people have strong opinions about.

Simply you don't need those thick radiators unless you really want to show off thick radiators. Instead get a thinner one that your case can accommodate and use push/pull with GT AP-15's and a fan controller like the Aquaero 6. Or you can get the GT PWM models and use with the Aquaero 6 to regulate your fan speed based on the current temperature.

Edit:
Also the relationship between Scythe and Nidec is now dead, but Nidec owns the trademark for "Gentle Typhoon" plus the patent for the fan design, I think, and the motor/bearings. We will see Gentle Typhoons again but when they will be back is not known (there is still stock of Scythe GT, but no one has seen other branded GT's yet).

 

[smackababy]

You're right; there is no point arguing because BrightCandle is 100% correct. Your "estimation" of 1 120mm per component + 1 extra is based on nothing. If OCN preaches that, I am glad I am not a part of that community; because, it is full of bad information.

 

[badb0y]

Hmm, so should I go for 2x 360mm rads because I will be pumping high voltages and max overclocks wherever I can.

Also I was under the impression that thicker rads = more surface area and more room for heat dissipation. If the thicker radiators don't perform better than the thinner ones I'll just grab the thinner radiators since they are cheaper.

 

[BrightCandle]

Thicker rad is about 130 watt dissipated compared to a thin rad being 90W dissipated.

 

[badb0y]

bump

OP updated