how many radiators?

[Memphis Raines]

I have been going through refreshing a friends Pc with a 980Ti in another thread... but in looking around at other builds I have seen that lots of people are using huge amounts of radiators in their builds..

The system is a 4770K @ 4Ghz and it has been running an overclocked 7970 gfx card in the same loop with a single 240mm rad with 2 static pressure fans blowing air in from the front of the case

It has always worked fine, and unless its getting maxxed out by a game its pretty silent most of the time..

the 7970 is getting replaced by a 980Ti.. which has a lower TDP so i expect no problems maintaining this current setup?


What confuses me is why i see builds with 2 or 3 radiators in them.. ok some are SLI systems but most have the same or similar CPUs and much bigger cases.

Am i missing something? am i under cooling my system? (it never gets past 60 degrees in games GPU or CPU)

or do people just like spending money on unnecessary parts?

the system:

Spoiler

 

[Greebo]

A
Or will depend on how much you intend to over lock the 980ti.

I had a i7 950 running at 4.2ghz and an over locked 7970 and my triple rad and single rad could easily keep all that cool. In fact could handle browsing passively.

In gaming the fans were on tickover and cpu would hit 50c and the 7970 from memory would never hit 50c .
However I have swapped to two 290x and a 5820k and 480mm of rad isn't up to the job anymore.
I have to turn the fans up to halfway so would like more cooling to be honest.

I suspect 240mm rad won't be enough for your rig unless u run the fans high

 

[Anonagrog]

All you're trying to do is take the watts of heat generated along the loop and dissipate it at an adequate rate. In the context of radiators, you obviously look at increasing the surface area for cooling (longer, thicker, or additional rads), or you look at increasing the airflow through the rads.

There are loads of 'rules' out there you could go by ("120mm per each component", "240mm for the first 2 big components, then 120mm for each thereafter", etc), but really it's best to look at how much heat your system will be generating, because TDP of components can vary by quite an amount, and this is ultimately what you're going to need to deal with to achieve your desired temps at peak load. What RPM fans you want to use, push-pull, the rad fins-per-inch, different thicknesses of rad, etc, may all have an effect on things too.

A general figure I use is 120mm per 100-150 watts of heat (low-rpm fans to high-rpm), which targets single rad fans handling idle-load temps across a range of 900-1800 RPM. It's hardly rigorous, but you can certainly see some pattern were you to analyze the various rads results/reports online. I'd also say that if you're after a 'silent pc' with fixed low-RPM fans (~1000 rpm) or aren't fussed about high-RPM (2000-3000) noise, you'll likely want to add or remove an extra 120mm rad length respectively as you approach ~400 watts of heat:

1 CPU (90w) - 120mm
1 CPU + 1 GTX 970 (90+145) - 240mm
1 CPU oc'ed + 1 AMD 7970 (110+250) - 360mm
1 CPU oc'ed + 1 GTX 980Ti (110+250) - 360mm
1 CPU oc'ed + 2 GTX 980Ti's oc'ed (110+2*275) - 2*360mm (could add or remove one or two 120mm lengths depending on either extreme with the fans).

Given that I don't have much to contend with weather-wise (20 deg C avg.), I just try to keep in and around the 50-60 C mark at load and keep an eye on my 'ambient air in' vs 'rad water out' temp deltas for good measure. It's worth considering that you're not very likely to reach that TDP under load, except for overclocked components. Also, in most games you're very unlikely to fully utilize both the cpu and gpu (SLi loses some on the scaling losses too) at the same time, so there would be less heat to deal with. In your case I'd have thought an oc'ed CPU + 7970 would be pushing it a bit (unless you're running a fat rad or high-rpm fans?), though it seems fine for you as you said. Can only go on best guesses. The error grows as you tackle more heat and components, so this radiator-fan guesstimate rather quickly becomes less "estimate" and all "guess".

 

[Glanza]

I'm currently running 3x 360mm rads as I went from a sli setup to 1 980ti another will be added later. I have a 4770k clocked at 4.5 and my temps on a full load never go over 36c now.

Thats with CPU / GPU and mosfets all on the same loop. If I saw 60c I'd be worried but that's just me.

 

[Anonagrog]

I'm currently running 3x 360mm rads as I went from a sli setup to 1 980ti another will be added later. I have a 4770k clocked at 4.5 and my temps on a full load never go over 36c now.

Thats with CPU / GPU and mosfets all on the same loop. If I saw 60c I'd be worried but that's just me.

That's impressive. With 3 triple radiators and only ~350 watts of h/w I'd think everyone would be worried with highs of 60C, even in hot climates and mildly low-rpm fans. What water-air delta T do you get under load, assuming you have a sensor? Much less than 5C?

 

[Memphis Raines]

That's impressive. With 3 triple radiators and only ~350 watts of h/w I'd think everyone would be worried with highs of 60C, even in hot climates and mildly low-rpm fans. What water-air delta T do you get under load, assuming you have a sensor? Much less than 5C?

I think you've miss read his comment...

 

[Anonagrog]

I think you've miss read his comment...

Did I... how so? :/

He/she uses 3 triple rads; had SLi but now uses one 980Ti, but will get another later; overclocks a 4770k to 4.5GHz and load temps never go above 36C; uses mobo blocks; would be concerned if they saw 60C with their set up, but that might just be him/her.

Given the hypothetical I'd think it's not just them that would be "concerned" but everyone, given temps of 60C with that set-up, even in warmer weather. Them having a load temps of 36C is pretty impressive, and so with all those rads I assume the loop has a good delta T. That or the ambient is pretty chilly.

 

[BluD]

Maybe he means he would be worried if he saw 60 degrees on any water rig, not specifically his rig. I wouldnt be worried about 60 degrees or even 70 degrees as long as you have good contact with the blocks and the water temp levels out before it gets too warm.

3x360s for a cpu and nividia gpu is pretty cool though , i remember reading sumwhere that a typical 360 rad can remove bout 200 watts at tickover on fans, and maybe 500w on 1500 rpm, so im guessing you could just turn off the fans to one of the rads for now and still keep the water temps just above room temp.

 

[spikerules]

Hang on. CPU AND GPU load temps never go over 36? Really? Or did you mean GPU only in that regard?

 

[Greebo]

Maybe he means he would be worried if he saw 60 degrees on any water rig, not specifically his rig. I wouldnt be worried about 60 degrees or even 70 degrees as long as you have good contact with the blocks and the water temp levels out before it gets too warm.

3x360s for a cpu and nividia gpu is pretty cool though , i remember reading sumwhere that a typical 360 rad can remove bout 200 watts at tickover on fans, and maybe 500w on 1500 rpm, so im guessing you could just turn off the fans to one of the rads for now and still keep the water temps just above room temp.

I used to be able to browse the internet passively with a triple rad and a single rad with my 7970 and i7-950. I love the silence

Im doing a new build for my 5820k and two 290x, im going for at least two 480 rads. I might try and keep the 360 rad in from before as well and see if i can browse passively again

 

[Glanza]

I'll rephrase if I saw my rig hitting 60c I'd be worried something was wrong with it.

Hang on. CPU AND GPU load temps never go over 36? Really? Or did you mean GPU only in that regard?

36c for both, once everything's up to running temps they level out the same.

 

[BluD]

Wow i wish mine did, i find the massive DIE on the gpus transfers heat into the water a lot better giving me a smaller difference between the water temp and the GPU core temp. I even use liquid metal on my CPU die and it still runs at completely different temps to the GPU. So it normally means i end up with the CPU temps jumping from a few degrees above water temp to 30+ degrees above water temp from one second to the next, where as my GPU temps rise and fall a lot slower and correspond to the water temp more consistently.

Im guessing your just running everything on a lot lower voltage than me though so its keeping your temps right down close to your water temp.

 

[Glanza]

At idle my cpu runs a few degrees hotter then my gpu but the water from the gpu goes straight into my cpu. On a full load it levels out the same.

I'm only doing a modest overclock on my cpu @ 4.5 and my 980ti is currently running stock voltage as I've no need to clock it just yet.

 

[Greebo]

And that is why i always go for overkill on my water loops.

Silence, low temps and future proofing if you then add a 2nd gpu

I had 480mm of rads on a i7 950 and 7970 which was fine.

I am now going for either 960mm or prob 1320mm of rads on my 5820k and 2 290x which will hopefully give me the same overkill of cooling like i had before.

 

[Deathjester]

You don't NEED that much radiator space:
I have a 4760 with a 970 just using a 240mm rad.
However I also have dual titans & a 4930K (also cooling the RAM and Mobo) with:
2x 480mm + 240mm (1200mm of Rads).

It's always about trade offs, obviously the 4760 and 970 the fans have to run much faster to keep the temps the same as the larger PC; or it just runs hotter.

 

[Greebo]

lol says the man with 120mm less rads than i am proposing

I know 2 x 480mm will be fine but want a bit of headroom.

hell even one 480mm is coping cooling my system atm but i have to run my fans above minimum to keep everything in check when gaming.

 

[Memphis Raines]

Space is a premium in the Prodigy case unfortunately.. I'd have liked to go with dual 240s but it won't fit..so any expansion is limited to a 120 or 140 exhausting at the rear or move the w
240 to the top and possibly a 180 at the front instead..tho they are much more expensive than more std sizes

 

[Deathjester]

Space is a premium in the Prodigy case unfortunately.. I'd have liked to go with dual 240s but it won't fit..so any expansion is limited to a 120 or 140 exhausting at the rear or move the w
240 to the top and possibly a 180 at the front instead..tho they are much more expensive than more std sizes

Yeah a 240mm was all that would fit in my Corsair 250D case as well (slim line one at that too)