Dual GTX 980 + CPU system recommendations

[Sailing_Nut]

Hi all!

I read over the n00b guide and have a basic idea of what I want to do.

I want to upgrade my PC to a dual GTX 980 (not TI version) system and water cool the GPUs and CPU. I'm not really concerned about OCing the CPU but I do want to push the GPUs some.

Will a single loop system be adequate for what I want to do or will I need a dual loop to get any reasonable OD out of the GPUs?

Also looking for recommendations on what size radiator would be adequate for this setup. I don't want to cheap out but I don't want to over buy either.

I'll also take any other insight/suggestions anyone wants to offer!

TIA!

 

[EarthDog]

Single loop is fine...

Which CPU are you using? The 980s at stock are 165W cards. At worst, 200W with some overclocking. That is 400W. I will assume you are cooling around 500W so I would say 5x120mm would keep things cool and quiet.

 

[Sailing_Nut]

Thanks!

I have a Core i7 3770K CPU.

Any advantage to going to a 140mm or higher rad?

 

[ATMINSIDE]

I'm assuming you're gaming?
What resolution are you at? Dual 980's for 1080p would be a waste of money.

 

[EarthDog]

Thanks!

I have a Core i7 3770K CPU.

Any advantage to going to a 140mm or higher rad?

Not really... there are not as many options for good fans for it is the reason I say that.

 

[Sailing_Nut]

Yep gaming on a triple monitor system at 5760 x 1080.

Currently have a dual R9 280x setup playing Skyrim. Want to beef up the cards for Fallout 4.

 

[NZKshatriya]

He could share the second one with me, just kidding...*shuts self in closet due to GPU embarrassment*

Agreed tho.
Used to be on the wanting Crossfire/SLI bandwagon, till pricepoints/heat and capabilities vs what I need came into play.

 

[Sailing_Nut]

He could share the second one with me, just kidding...*shuts self in closet due to GPU embarrassment*

Agreed tho.
Used to be on the wanting Crossfire/SLI bandwagon, till pricepoints/heat and capabilities vs what I need came into play.

Going to be selling the old cards on eBay ;-)

 

[ATMINSIDE]

Yep gaming on a triple monitor system at 5760 x 1080.

Currently have a dual R9 280x setup playing Skyrim. Want to beef up the cards for Fallout 4.

Good I'm running my 5760x1080 on a single 980, you'll be very happy with your choice.

What case are you using? I'd be looking to grab a 360mm and 240mm radiator to cool your setup.

 

[Sailing_Nut]

Using a Rosewill THOR 2 case. Lots of good interior space!

 

[ATMINSIDE]

Do some research about your case and make sure the max thickness of rads you can fit.
Don't forget about where the fans will go as well.

 

[Sailing_Nut]

Do some research about your case and make sure the max thickness of rads you can fit.
Don't forget about where the fans will go as well.

Thinking That for simplicity of build and for better cooling efficiency I would go with an external rad. Good or bad idea?

 

[GTXJackBauer]

Yep gaming on a triple monitor system at 5760 x 1080.

Currently have a dual R9 280x setup playing Skyrim. Want to beef up the cards for Fallout 4.

I would steer away from 4 GB GPUs. I honestly would advise on saving a bit more and grabbing 2 GTX 980 Ti's with 6 GB of Vram. In DX11, let alone 12 is pretty much on its way, in surround in BF4 with settings full, its eating up my 3GB. You don't think they will eat up 4 GB in the next couple of years if not a lot sooner? Again, 2x GTX 980 Ti 6 GB for 5760x1080 would be ideal and killer.

Using a Rosewill THOR 2 case. Lots of good interior space!

Start looking to go external because that's a horrible case for a custom liquid loop. It wasn't mainly designed for water cooling but lots of air cooling. Have a look at MORA 3 rads. Do some research and find some external setups with that rad and how things are mounted.

Here's a recent post in the cooling section of a nice external custom loop setup. Just use QDC's (Quick Disconnects) to and from the PC via tubing holes.

 

[EarthDog]

Thinking That for simplicity of build and for better cooling efficiency I would go with an external rad. Good or bad idea?

my personall feelings are that most external setups just look hideous.

I wouldn't worry about 6gb card there personally... you are going to be able to lower AA a notch if things get wonky. It is the minimum for sure.

 

[Sailing_Nut]

Single loop is fine...

Which CPU are you using? The 980s at stock are 165W cards. At worst, 200W with some overclocking. That is 400W. I will assume you are cooling around 500W so I would say 5x120mm would keep things cool and quiet.

How does one go about calculating what size rad is required for a given heat dissipation?

I've done a bit of Googling and have come up empty.

TIA!

 

[EarthDog]

It will vary depending on the radiator. 100W x120mm is a decent rule of thumb.

 

[Sailing_Nut]

It will vary depending on the radiator. 100W x120mm is a decent rule of thumb.

So by taking that rule of thumb I can calculate that it is recommended to have 144 square mm per watt of heat to be dissipated. (I know this is very rough because it's all about the surface area presented by the rad and that depends on thickness, fin density, etc.)

Expanding that out a dual 200mm fan rad should be capable of dissipating 600W of heat.

Anyone care to poke holes in my generalization?

Just want to make sure I don't under size my rad!

 

[EarthDog]

You can't go by that, no... there are other variables involved. For example FPI plays an important role in how much heat a rad can dissipate.

Take a look at specifications of the radiators you are looking at from their website. It usually shows how much heat it can dissipate (though they are generally inflated).

 

[NZKshatriya]

Size, materials, airflow, quality of machining, etc.

 

[Sailing_Nut]

Figured I was oversimplifying with that calculation! That's why I threw it out here instead of designing with it!

I looked as several radiators (both before and after writing the post) and I have not found any that specify how much heat that they can dissipate. I must be choosing poorly on brands.

Any suggestions on good brands that actually specify their heat dissipation capabilities?