Radiator size i7 8700k and GTX 1080TI

[Generation]

Hi,

Since this seems to be the place to be where water cooling knowledge is and I couldn't really find anything on google with my specific use case.

 

I got:

i7 8700K @ 5GHz Delidded  , currently running a kraken X52  (240 rad)

GTX 1080 Ti Aorus (normal version)  Currently set at 150% Power limit.

In a Corsair 570X case

6x HD120 Corsair fans.

I ordered:

EK Supremacy EVO RGB CPU block

EK-XRES 140 Revo D5 RGB
Magicool G2 Slim Radiator  (360mm Rad, 27mm thick)
All 16mm (5/8) PETG tubing 

 

I am new to custom watercooling, I am new to rigid tubing. I am confident this will not be too much of an issue. Afterall I could get some 90-degree fitting if I cant manage.

 

However, if I want to include my GPU in the loop. Would this radiator still be enough or would I need to place additional 240 up top?

 

[Skiiwee29]

360mm rad should be plenty. There is debates that in general when you run multiple items you should have 240mm per item, but 360 should be sufficient. 

[Sacredsock]

I don't have a lot of experience with water cooling, but the comment I usually come across is 120mm for each component in the loop.

What I would say is that by that logic a 360 should be sufficient, I guess it would depend how hard you plan on pushing the hardware.

You can always play around a little on the EK website as they have a configurator.

[Generation]

@Skiiwee29 Wow thats a fast reply.

 

I know about the rule of thumb for about but 4 factors made me doubt.

-my rad slim

- i7 8700K overclocked 

- GTX 1080 ti overclocked

- Corsair 570x case not the best in airflow (guess)

 

@Sacredsock I'll go over there now and play with it.

Thanks for the help so far guys! much appreciated 

 

[Skiiwee29]

Just now, Generation said:

@Skiiwee29 Wow thats a fast reply.

 

I know about the rule of thumb for about but 4 factors made me doubt.

-my rad slim

- i7 8700K overclocked 

- GTX 1080 ti overclocked

- Corsair 570x case not the best in airflow (guess)

 

@Sacredsock I'll go over there now and play with it.

Thanks for the help so far guys! much appreciated 

 

570x actually is a much better case for airflow than you think. Its actually one of the better ones.

 

[For Science!]

2 minutes ago, Generation said:

@Skiiwee29 Wow thats a fast reply.

 

I know about the rule of thumb for about but 4 factors made me doubt.

-my rad slim

- i7 8700K overclocked 

- GTX 1080 ti overclocked

- Corsair 570x case not the best in airflow (guess)

 

@Sacredsock I'll go over there now and play with it.

Thanks for the help so far guys! much appreciated 

 

ive found a 360 rad to be only just enough for the 8700K and 1080Ti. if you have the space, get an extra 240mm

 

See my Ncase M1 log for more details.

[Generation]

@Skiiwee29 Well. That shines a new light on it.

 

@For Science! Thanks!. Considering your small form factor and my big case I think it should be able to do with just one 360 rad. (according to benchmarks the Magicool G2 is better than the EK 360 SE)


Also from EK Site with the pre-listed config and only one 360 SE in front.

 

 

 

You guys have been very helpful. I have my answer within the hour, amazing.
 

[Maticks]

One 360mm will be enough 8700ks don't generate that much heat and it's only one 1080ti. Two 1080tis you'd need 480mm. 1000rpm on those fans you will have good temps.

 

I'd go 90 degree fittings for your first build with pegt, then you only need to do one bend where needed. It does help a lot. Second system you learn from the first and can do multiple bends. Always remember to smooth the end of the cut inside and out so you don't cut the edge of your oring seals in the fittings. They are your defence against leaks if it's not all the way in. Apart from that have fun

[Generation]

44 minutes ago, Maticks said:

.

 

I'd go 90 degree fittings for your first build with pegt, then you only need to do one bend where needed. It does help a lot.

2

Im stubborn, First gonna try to do multi bend. haha.

still need to order GPU waterblock so if i need more PETG or fitting like 90 degree, i can order it with that.

While we are on the subject. I use the EK HDC fittings, would i need to buy 2 fittings and one 90 degree piece to make it work ?

[AngryBeaver]

4 hours ago, Generation said:

Hi,

Since this seems to be the place to be where water cooling knowledge is and I couldn't really find anything on google with my specific use case.

 

I got:

i7 8700K @ 5GHz Delidded  , currently running a kraken X52  (240 rad)

GTX 1080 Ti Aorus (normal version)  Currently set at 150% Power limit.

In a Corsair 570X case

6x HD120 Corsair fans.

I ordered:

EK Supremacy EVO RGB CPU block

EK-XRES 140 Revo D5 RGB
Magicool G2 Slim Radiator  (360mm Rad, 27mm thick)
All 16mm (5/8) PETG tubing 

 

I am new to custom watercooling, I am new to rigid tubing. I am confident this will not be too much of an issue. Afterall I could get some 90-degree fitting if I cant manage.

 

However, if I want to include my GPU in the loop. Would this radiator still be enough or would I need to place additional 240 up top?

 

If you aren't planning to do any real overclocking then a 360mm should be fine, but you are planning to overclock both components. So a 360mm especially the slim version, will be pushing it.

 

In general the old rule of thumb is 120mm for each component you want to cool plus an additional 120mm for each one you plan to overclock. However both of the components you picked run pretty darn hot... so having at least 480mm of rad surface area would be best. So if you can I would definitely add the other 240mm radiator you mentioned. Having more rad space than needed isn't a bad thing, it will slightly improve your deltaT or means you can run your fans at lower rpms thus making your system much more quiet.

 

Just remember it is always better to have more Rad space than is needed instead of less. Also since you are going to be delidding your cpu, you will see better results from the increased cooling capacity. 

 

On second glance I see you don't have anything order to actually water cool the gpu. So if you aren't planning to water cool the gpu then the 360 is fine. I would say though it is silly to invest in a custom loop if you aren't going to add the gpu to it though.

[AngryBeaver]

2 hours ago, Maticks said:

One 360mm will be enough 8700ks don't generate that much heat and it's only one 1080ti. Two 1080tis you'd need 480mm. 1000rpm on those fans you will have good temps.

 

I'd go 90 degree fittings for your first build with pegt, then you only need to do one bend where needed. It does help a lot. Second system you learn from the first and can do multiple bends. Always remember to smooth the end of the cut inside and out so you don't cut the edge of your oring seals in the fittings. They are your defence against leaks if it's not all the way in. Apart from that have fun

I just wanted to address this post in particular.

 

First an 8700k WILL produce a lot of heat. On average it looks like a 8700k at 5ghz will pull about 220-240 watts of power at load. Remember TDP of a chip goes out the window when you run multicore enhancement or overclock the chip.. even then turbo boost can push tdp to almost double the rated level.

 

So that brings us lets say 230 TDP of heat to dissipate under load with the overclock OP wants. A stock 1080ti pulls about 280 TDP. However, when overclocked this shoots up to as high as 350 TDP. So now we have to account for that heat too. So if we look at all of the factory overclocked cards we can assume that most 1080tis will be in the 300-320 range without touching a single thing overclock wise. So lets go with 320 for giggles.

 

That means we have 550 TDP of heat to dissipate. That thin 360mm rad you showed is quoted at having 413w of dissipation. That means you will need extremely high airflow fans (loud) or be willing to have a much higher deltaT (higher system temps).  You could choose to go with a much better radiator like a black ice, but you will still need decent air flow.

 

You could alternatively add that other 240mm rad and assuming it isn't low fpi or slim... you could expect another 280-300 watts of cooling power.

 

So that would bring your total cooling power to 690-720 TDP. So that gives you a decent amount of headroom for the 550 TDP you would see under a heavy gaming load. Meaning you can run lower rpm fans, or at least allow the fans you use to run slower (less noise). You also have some headroom in the event you add a different gpu in the future with higher TDP... or cpu.  Now these are high usage scenarios, but in a demanding game you can expect to see TDP around what I am giving you... I mean the numbers aren't exact by any means, but they will be within about 10% of real world scenarios. So 500-600 watts could be the full usage area.

 

Anyways I just wanted to give some numbers and facts. It would be terrible for you to take all this time ordering stuff and planning your hardline loop... only to need to pull it apart in a few days/weeks because the cooling capacity isn't where it needs to be.

 

Just to elaborate more. The estimator used on that site... basically adds the manufacturer provided TDP of components... without would be 95w for the cpu and 250 or 345 watt (which it is also showing less than). TDP from manufacturers isn't by any means a good thing to go off of. As the TDP of a cpu can easily spike to almost double its rating when under turbo boost or doing certain instruction sets. The GPU one accounts for a stock reference card and doesn't account for boost load or that of factory overclocked cards. So don't put much faith in these system estimator calculations... instead you need to do some independent research either via reviews or by having the experience to know what to expect.

[Generation]

@AngryBeaver   Thank you for sharing your knowledge, very very helpful for the newbie in watercooling. I am amazed how helpful this forum is, the local forums I know are either inactive or quite .... toxic...   I appreciate the time you took to type such a lengthy and well-supported response

 

The PC is already running and indeed pulls around 550 from the wall at peak moments. (this includes several USB devices and RGB strips, HDD/ssd's)

i7 is running the stable overclock @ 5Ghz, I did reach 5,2 but for the daily I'm keeping it on 5 with around 1.27 Vcore.

 

 

to get list:

 

240MM rad

   Either: XSPC EX240 Crossflow
     Or: Magicool G2 Slim Radiator 16 FPI         Depending on whether I want/need crossflow, whatever gives me the cleanest looking loop 

 

Full GPU Block

Either EK Plexi with nickel backplate

Or the Phanteks (which has RGB, and I'm a sucker for)    Both cost the same, however since most of it is EK, I'm leaning towards EK since I got most of my stuff from them.

 

4 additional fittings... damn those things really add up haha

 

 

 

My CPU loop will come in tomorrow and I can start building it, from there I will device what I need to order more to make it work. (I just might be a PETG bending god, who knows )

I do have a 2nd pc with decent graphics where I will soon move the AIO cooler too, I have no rush in building and I can take my time and wait for parts to come in (although very eager to start). I will see then if i need 90 degree bends with fittings or a 90 degree with integrated fittings if such a thing exists with EK.

 

 

 

[Maticks]

With the 90 degree fittings you need to buy the connection fittings for you od size the inner will be standard. Be the size of your petg. At 1.27volts it's really not that much heat out of The CPU. Might be 5c warmer on the cpu if the loop is at 30c water wise but you can pump up fans a bit to pull out that heat. With good airflow it's really not that bad.

If really needed try push pull. Can squeeze a bit more performance out of the radiator if wanting to really push overclocking.

 

 

[AngryBeaver]

1 hour ago, Maticks said:

With the 90 degree fittings you need to buy the connection fittings for you od size the inner will be standard. Be the size of your petg. At 1.27volts it's really not that much heat out of The CPU. Might be 5c warmer on the cpu if the loop is at 30c water wise but you can pump up fans a bit to pull out that heat. With good airflow it's really not that bad.

If really needed try push pull. Can squeeze a bit more performance out of the radiator if wanting to really push overclocking.

 

 

So out of curiosity what is your motive behind trying to push him for only using a 360mm slim rad, when it has already said he was willing to add another 240mm? When given two options why would you choose the less efficient and inadequate option? I mean, technically you could just use a 120mm rad for both items, but the heat penalty you would pay wouldn't be worth it.

 

Something else I want to point out. Dissipation of an item is determine by several things. The difference between the water and the outside ambient temp, the amount of surface area, and the airflow over that area.

 

So the higher the difference in the temp of your water and ambient then the more heat that can transfer to the air at a given time... the problem here is that water temps directly impact component temps which is why aiming for a decent deltaT is important. Most aio's are in the 10-15 range, where as custom loops are in the 5-10 range.

 

The surface area of an item is determined by actual size of the rad (length, height, depth) The FPI (fins per inch). So the more surface area you have the more contact it has with the air and the more heat that can transfer out. High FPI rads require more static pressure fans, but can transfer a lot more heat. A low FPI rad can move heat better at lower RPM's, but the problem is it caps out the effect air flow has on it. Meaning after a certain and generally medium rpm range.. it will not gain any more cooling power from more air flow... that is not without the first thing I mentioned increasing which is water temp vs air temp.

 

So with that 360mm Rad he has is a slim one and is only 16 fpi. Which isn't bad, but means it will gain limited benefit from just throwing some high flow high rpm fans on it in push pull. Now if he had a single 3x140mm= 420mm that was of a moderate thickness with say a 19+ fpi (a 19 fpi split fin would be great here) then I would probably been more inclined to agree with you. For example a EK coolstream CE 420 with only 16 fpi, but a decent thickness can dissipate about 515watts of heat at 1850 RPM. So while this is barely enough and it would probably see the deltaT creep to 11-12c at stress testing levels... it would still perform decently.

 

The thing is though... once you add in another 240mm rad in the above situation.. that means your delta T would be around 5c with the extra rad (will be similar with his 360). So that would drop his temps 7c across the board, which doesn't sound like a lot, but 7c can easily be the different from a stable overclock and an unstable one. Also he would run in the 5-7c range with much lower fan rpms. So his machine would be much more quiet, while his performance would also be much better.

 

Just some food for thought.

[MaratM]

If there is a possibility to use second 240 rad use it.

Both of your components produce a lot of heat then OC and 360 rad is not really enough to make your system quiet at load. You can always use noctua industrial fans (3000 rpm) but they are loud at 3000 rpm.

[Maticks]

If he can add a second radiator the do it, they are cheap vs the rest of the loop. I'm just saying can you g t by with one 380. Yes..  a second radiator will allow more overclocking.

I'm more a 480mm monsta person and use those in my builds, but you need a big case for that. The second reason I use that radiator I can put connections at the top and a drain port on the bottom of it. Not many radiators are setup like the monsta