Radiator Size for CPU + GPU

[Titan343]

Hi all, I am doing a custom looped liquid cooled build. It has an EVGA 980 Hydro Copper and Intel i7-4790k. The total TDP is 223, I plan to use the Alphacool NexXxoS Cool Answer 360 D5/ST kit which has a 360 rad and D5 pump. I cannot find any info for the radiator to TDP performance. Is it a good choice for kits? I plan to extend it to include the GPU so will I need any more fittings? I will be changing the coolant to the Mayhem Pastel concentrate. For expansion purposes will it still be suitable for 2 980s? Thanks!

 

[JackNaylorPE]

Please note that the EVGA Hydrocopper does a great job on GPU cooling but is not good at all on VRM and VRAM cooling .... VRAM temps are about 30C hotter than EKs block which will significantly hamper your overclocking ability.

The 4790k can output about 140 watts overclocked to 4.6-ish @ 1.4 volts.... Using Afterburner to set 110% TDP for the GPUs, that puts ya GFX card load at 245 or so.

That puts your load at 140 + 2 x 245 + 20 for pump or 650 watts. The rads need to handle about 60% 0f that or 390 watts.

The Alphacool ST30-360 is capable of the following at 10C delta T:

With 1,000 rpm fans the ST30-360 provides 150 watts of cooling, 182 in push / pull

With 1,250 rpm fans the ST30-360 provides 181 watts of cooling, 219 in push / pull

With 1,400 rpm fans the ST30-360 provides 199 watts of cooling, 241 in push / pull

With 1,800 rpm fans the ST30-360 provides 242 watts of cooling, 293 in push / pull

With 2,200 rpm fans the ST30-360 provides 281 watts of cooling, 340 in push / pull

At 2,200 rpm, you'd have a delta T of about 390/340 x 10 or 11.5C

Fans become audible at about 850 cfm on a radiator .... at 1250 rpm they get progressively more annoying .... at 2200 and above we are talking vacuum cleaner like.

If ya want the data behind the above, it can be found here.

http://www.overclock.net/t/1457426/radiator-size-estimator

The old rule of thumb came long before the days of 300 watts GPUs so no longer applies despite the efficiency of the new 980 series. For a Delta T Target of 10C:

At 1,000 rpm... each 120mm of radiator is good for about 83 watts of total load.
At 1,250 rpm... each 120mm of radiator is good for about 105 watts of total load.
At 1,400 rpm... each 120mm of radiator is good for about 117 watts of total load.
At 1,800 rpm... each 120mm of radiator is good for about 145 watts of total load.
At 2,200 rpm... each 120mm of radiator is good for about 170 watts of load.

Add 36% for 140mm rads
Add 21% for push / pull

Here's the original data source
https://martinsliquidlab.wordpress.com/2012/05/01/alphacool-nexxxos-st30-360-radiator/4/

As you will note radiator thickness has a miniscule part to play until you get to high fan speeds

1250 rpm
ST30 (30mm) - 60 watts of cooling per 120mm
XT45 (45mm) - 61 watts of cooling per 120mm
UT60 (30mm) - 63 watts of cooling per 120mm
Monsta (80mm) - 66 watts of cooling per 120mm

1800 rpm
ST30 (30mm) - 81 watts of cooling per 120mm
XT45 (45mm) - 86 watts of cooling per 120mm
UT60 (30mm) - 90 watts of cooling per 120mm
Monsta (80mm) - 94 watts of cooling per 120mm

At 2,200 rpm we start to see the Monsta show its mettle, but Id be hard pressed to sit in the room at even 1400 rpm

ST30 (30mm) - 91 watts of cooling per 120mm
XT45 (45mm) - 102 watts of cooling per 120mm
UT60 (30mm) - 109 watts of cooling per 120mm
Monsta (80mm) - 122 watts of cooling per 120mm

I'd do spme research into Aurora 2 and make sure you wanna "go there" with Aurora (yes Im talking about version 2) with a 3 block loop.

Also Mayhems coolants has a bit of an issue with Alphacool rads.... you will need to use the $50 Mayhem,s Blitz kit before using Mayhems coolants. See the Mayhems Owners Club thread on overclock.net

 

[maddogfargo]

I'd suggest a 45-60mm thick, 360-480mm long all copper rad.

The Alphacool UT is the 60mm thick version. Not sure of the thickness on the ST. But the D5 pump should be plenty for the GPU + CPU blocks.

A very basic rule of thumb for 45-60mm rads is 1x120mm fan per high TDP block. So in theory, a 360mm rad should be enough for a CPU + 2 GPUs, especially since Maxwell isn't quite as hot as previous generations of nVidia and AMD GPUs.

 

[Titan343]

Please note that the EVGA Hydrocopper does a great job on GPU cooling but is not good at all on VRM and VRAM cooling .... VRAM temps are about 30C hotter than EKs block which will significantly hamper your overclocking ability.

The 4790k can output about 140 watts overclocked to 4.6-ish @ 1.4 volts.... Using Afterburner to set 110% TDP for the GPUs, that puts ya GFX card load at 245 or so.

That puts your load at 140 + 2 x 245 + 20 for pump or 650 watts. The rads need to handle about 60% 0f that or 390 watts.

The Alphacool ST30-360 is capable of the following at 10C delta T:

With 1,000 rpm fans the ST30-360 provides 150 watts of cooling, 182 in push / pull

With 1,250 rpm fans the ST30-360 provides 181 watts of cooling, 219 in push / pull

With 1,400 rpm fans the ST30-360 provides 199 watts of cooling, 241 in push / pull

With 1,800 rpm fans the ST30-360 provides 242 watts of cooling, 293 in push / pull

With 2,200 rpm fans the ST30-360 provides 281 watts of cooling, 340 in push / pull

At 2,200 rpm, you'd have a delta T of about 390/340 x 10 or 11.5C

Fans become audible at about 850 cfm on a radiator .... at 1250 rpm they get progressively more annoying .... at 2200 and above we are talking vacuum cleaner like.

If ya want the data behind the above, it can be found here.

http://www.overclock.net/t/1457426/radiator-size-estimator

The old rule of thumb came long before the days of 300 watts GPUs so no longer applies despite the efficiency of the new 980 series. For a Delta T Target of 10C:

At 1,000 rpm... each 120mm of radiator is good for about 83 watts of total load.
At 1,250 rpm... each 120mm of radiator is good for about 105 watts of total load.
At 1,400 rpm... each 120mm of radiator is good for about 117 watts of total load.
At 1,800 rpm... each 120mm of radiator is good for about 145 watts of total load.
At 2,200 rpm... each 120mm of radiator is good for about 170 watts of load.

Add 36% for 140mm rads
Add 21% for push / pull

Here's the original data source
https://martinsliquidlab.wordpress.com/2012/05/01/alphacool-nexxxos-st30-360-radiator/4/

As you will note radiator thickness has a miniscule part to play until you get to high fan speeds

1250 rpm
ST30 (30mm) - 60 watts of cooling per 120mm
XT45 (45mm) - 61 watts of cooling per 120mm
UT60 (30mm) - 63 watts of cooling per 120mm
Monsta (80mm) - 66 watts of cooling per 120mm

1800 rpm
ST30 (30mm) - 81 watts of cooling per 120mm
XT45 (45mm) - 86 watts of cooling per 120mm
UT60 (30mm) - 90 watts of cooling per 120mm
Monsta (80mm) - 94 watts of cooling per 120mm

At 2,200 rpm we start to see the Monsta show its mettle, but Id be hard pressed to sit in the room at even 1400 rpm

ST30 (30mm) - 91 watts of cooling per 120mm
XT45 (45mm) - 102 watts of cooling per 120mm
UT60 (30mm) - 109 watts of cooling per 120mm
Monsta (80mm) - 122 watts of cooling per 120mm

I'd do spme research into Aurora 2 and make sure you wanna "go there" with Aurora (yes Im talking about version 2) with a 3 block loop.

Also Mayhems coolants has a bit of an issue with Alphacool rads.... you will need to use the $50 Mayhem,s Blitz kit before using Mayhems coolants. See the Mayhems Owners Club thread on overclock.net

Can you recommend a better block and base card? Also is the 360 rad suitable or no? I got a bit lost in all the info, thanks!

 

[JackNaylorPE]

http://www.overclock.net/t/1505481/summer-water-block-round-up-2014

EK Supremacy rules the roost across all platforms

http://www.xtremerigs.net/2013/10/03/nvidia-gtx780titan-water-block-roundup/2/
Here you can see that:

EK loses by 1C to the EVGA on GPU temps
EK wins by 10C over the EVGA on VRAM temps
EK wins by 30C on VRM temps

As for your rad question .... you need to provide some answers as to what your "design conditions" are.

1. What are you building ?

Less than 5°C = Extreme system
Comprised between 5°C and 10°C = Extreme to High-end system
Comprised between 10°C and 20°C = High-end to Mid-range system
Comprised between 20°C and 30°C = Mid-range to Entry-level system

Given your component selection being 'high end", I used a Delta T target (difference in temp between ambient air and coolant) of 10C ... Shooting for 10C at 1200 rpm means ya can likely run any game or app ya want at about 850 rpm and have no fan noise.

2. What about noise levels ? These determine what fan rpm you can run.

With 390 watts, If ya shooting fro just one radiator.... XT45-420 would give you 250 watts of cooling at 1250 rpm, 302 in push pull

An XT45-420 ($85) on the top gives 250 plus a ST30-240 ($53) would add 130 for 380 watts and that system would run dead silent... and that's w/ just one fan per as as opposed to push/ pull

Would work real nice in an Enthoo Luxe case.

 

[Titan343]

http://www.overclock.net/t/1505481/summer-water-block-round-up-2014

EK Supremacy rules the roost across all platforms

http://www.xtremerigs.net/2013/10/03/nvidia-gtx780titan-water-block-roundup/2/
Here you can see that:

EK loses by 1C to the EVGA on GPU temps
EK wins by 10C over the EVGA on VRAM temps
EK wins by 30C on VRM temps

As for your rad question .... you need to provide some answers as to what your "design conditions" are.

1. What are you building ?

Less than 5°C = Extreme system
Comprised between 5°C and 10°C = Extreme to High-end system
Comprised between 10°C and 20°C = High-end to Mid-range system
Comprised between 20°C and 30°C = Mid-range to Entry-level system

Given your component selection being 'high end", I used a Delta T target (difference in temp between ambient air and coolant) of 10C ... Shooting for 10C at 1200 rpm means ya can likely run any game or app ya want at about 850 rpm and have no fan noise.

2. What about noise levels ? These determine what fan rpm you can run.

With 390 watts, If ya shooting fro just one radiator.... XT45-420 would give you 250 watts of cooling at 1250 rpm, 302 in push pull

An XT45-420 ($85) on the top gives 250 plus a ST30-240 ($53) would add 130 for 380 watts and that system would run dead silent... and that's w/ just one fan per as as opposed to push/ pull

Would work real nice in an Enthoo Luxe case.

HOWEVER, since only one card is going in right now, will that 360mm from Alphacool be fine in push/pull? It seems like it, any good cases for it?


Ok so it looks like the EVGA 980 with the EK-FC980 waterblock is what I am looking at getting:
http://www.performance-pcs.com/ek-fc980-gtx-waterblock-for-nvidia-980-gtx-nickel-acetal.html
http://www.newegg.com/Product/Product.aspx?Item=N82E16814487089

And for what it's worth the coolant:
http://www.performance-pcs.com/mayhems-pastel-red-concentrate-250ml.html#Features


1. Currently there is about $900-$1000 left (with only a single gpu). It should be extreme, but not double radiator extreme per say. The high end to extreme range sounds good, but depending on price to actual impact the high to mid is fine.

2. The noise level doesn't have to perfectly silent since the client lives on a high traffic street as they say so higher rpms are fine. I would prefer it to be in the push-pull config for max performance.

I am extremely interested in a kit that I can just expand to include the GPU since it is quite the hassle to get all the proper bits, there is a higher end kit available which has the D5 pump with a 480 rad.
http://www.aquatuning.us/water-cooling/kits-und-systems/internal-kits/16933/alphacool-nexxxos-cool-answer-480-d5/xt-kit?c=6460

 

[JackNaylorPE]

Again, historically, the EVGA SC is the weakest line of the Big 4 (Gigabyte Windforce / G1, MSI TWinFrozr4 / Gaming, Asus DCII / Strix. EVGA SC has typically been just a reference PCB with a better cooler whereas most everyone else adds larger VRMs, more phases, better chokes, better caps, direct contact memory and VRM cooling, etc. all of which factor in to better overclocks.

As to the Pastel, it is even more important... better said absolutely essential, that you use the blitz kit. I have Mayhems red in my build, it's now black.

The rads you have selected (8 - 12 fpi) are designed for for low rpm fans ... that's really WC's forte today as again, voltage rather than heat controls today's water clocks. The Enthoo Primo would look cavernously empty I think w/ just 1 rad. If you are going to use higher rpm fans, especially in push / pull, an XT45-420 in the Enthoo Luxe would be the better build.

And yes it is a project, one that should warrant detailed consideration before undertaking especially since the 980s present a relatively small head load as compared to say 780s or 290x's. You will get no greater overclocking performance out of a Dual Rad system with CPU and GFX water blocks as you would out of a Swiftech H240-X on a CPU and air cooled 980s. For example, I have not been able to get a MSI 980 over 63 degrees as yet.

Again, "extra thick" doesn't have a significant effect on cooling and anything over 45mm in push / pull presents a fit problem in the Enthoo Primo and most other cases. Look at my pics in the Enthoo Owners Club thread on overclock.net as well as Jesse's build over on the ModZoo site.

I'm doing a build in the next week with the Enthoo Luxe (white), a 2m Phanteks internal 2m LED strip, twin 970's and a 4690k.

 

[Titan343]

Again, historically, the EVGA SC is the weakest line of the Big 4 (Gigabyte Windforce / G1, MSI TWinFrozr4 / Gaming, Asus DCII / Strix. EVGA SC has typically been just a reference PCB with a better cooler whereas most everyone else adds larger VRMs, more phases, better chokes, better caps, direct contact memory and VRM cooling, etc. all of which factor in to better overclocks.

As to the Pastel, it is even more important... better said absolutely essential, that you use the blitz kit. I have Mayhems red in my build, it's now black.

The rads you have selected (8 - 12 fpi) are designed for for low rpm fans ... that's really WC's forte today as again, voltage rather than heat controls today's water clocks. The Enthoo Primo would look cavernously empty I think w/ just 1 rad. If you are going to use higher rpm fans, especially in push / pull, an XT45-420 in the Enthoo Luxe would be the better build.

And yes it is a project, one that should warrant detailed consideration before undertaking especially since the 980s present a relatively small head load as compared to say 780s or 290x's. You will get no greater overclocking performance out of a Dual Rad system with CPU and GFX water blocks as you would out of a Swiftech H240-X on a CPU and air cooled 980s. For example, I have not been able to get a MSI 980 over 63 degrees as yet.

Again, "extra thick" doesn't have a significant effect on cooling and anything over 45mm in push / pull presents a fit problem in the Enthoo Primo and most other cases. Look at my pics in the Enthoo Owners Club thread on overclock.net as well as Jesse's build over on the ModZoo site.

I'm doing a build in the next week with the Enthoo Luxe (white), a 2m Phanteks internal 2m LED strip, twin 970's and a 4690k.

Hmmm interesting, this is a client build and they wanted "extreme", but I agree with the 980 part. I will talk to them and work out a different solution. They wanted something showy but doesn't want a compacted look, tis the primo. What I am thinking is instead of a 980 is 2 MSI Gaming 970s with a 360mm XT45 rad on top in push/pull and a 240 Monsta or UT60 on the bottom in push/pull. Although since you are doing a build with 2 970s in the Luxe do you know a good placement for the rads?

Also I have heard that distilled water is praised for it not, uh, turning black, but it also requires a complete drain every 6 months, something that the client is not interested in. Can you recommend any other coolants? I primarily chose the pastel because, uh, Jayztwocents likes it.

I was browsing the Phantek Enthoo Primo club earlier and saw your build, sweet!

The fans are just the Phobya NB-eLoop 1600rpm (red).

I know that I keep asking a lot and am really appreciating all of your help, you will definitely get a best answer after this.

 

[Titan343]

I got the problem solved on a different forum but thanks for your help