Need Advice For 420mm 7970 Water Cooling Custom Loop

[24601]

Continued from here

http://forums.anandtech.com/showpost.php?p=35030526&postcount=22

It seems I'm forced to turn to water cooling to somehow keep 2x 7970 and 2x 7950 cool in 1 case.

I'm assuming I'll need 1-2x 420mm radiators and at least 2x 7970 full-length water blocks for the various cards I have.

7970 Cards:
SAPPHIRE 100351SR Radeon HD 7970 3GB 384-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card OC with Boost
http://www.newegg.com/Product/Produc...82E16814202008

XFX Double D FX-797A-TDBC Radeon HD 7970 Black Edition 3GB 384-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Produc...82E16814150586

7950 Cards:
SAPPHIRE 100352-2L Radeon HD 7950 3GB 384-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16814202006

HIS IceQ Boost Clock H795QC3G2M Radeon HD 7950 3GB 384-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161420


I have zero personal experience with water cooling so I would need much help with this endeavour :O

 

[T_Yamamoto]

I'm pretty sure you can use universal water blocks with some fins for the ram and such.

 

[BrightCandle]

If you want to use 140mm radiators then they are about 36% more cooling potential per fan than a 120mm radiator. I know from before you were talking about running these cards at their full 300W overclocked potential.

Given that a single 140mm fan running at 800rpm (almost silent, still audible close up but its quieter than any hard drive spinning for example so pretty darn quiet) then you are looking at about 150W at 10C per 140mm fan. 4 cards at 300W is 1200W so divide one by the other and you get 8 radiator slots in total. That would give you a water delta of 10C, which means your cards will idle in the 20's and under load get up to about 50C maximum.

If you halved the number of radiator slots, then that delta would slightly more than double (its linear enough in the bounds of 0-20C not too worry to much about the fact its not linear) so you would gain about 10-15C on the top temperature and still have a working system with only 4 radiator slots (a lot cheaper), but you can't put other components in that loop.

Ideally you will want full length blocks but neither of your cards are reference design which means that probably isn't an option. The problem with the generic blocks and heatsinks is the VRMs can get really hot with just stick on passive cooling. Its not really sufficient for an overclocked high end card and its easy to miss cooling something really important and blow the card up. I don't like the generic block approach, its a lot more risky and doesn't allow for the cooling of everything via water.

 

[24601]

If you want to use 140mm radiators then they are about 36% more cooling potential per fan than a 120mm radiator. I know from before you were talking about running these cards at their full 300W overclocked potential.

Given that a single 140mm fan running at 800rpm (almost silent, still audible close up but its quieter than any hard drive spinning for example so pretty darn quiet) then you are looking at about 150W at 10C per 140mm fan. 4 cards at 300W is 1200W so divide one by the other and you get 8 radiator slots in total. That would give you a water delta of 10C, which means your cards will idle in the 20's and under load get up to about 50C maximum.

If you halved the number of radiator slots, then that delta would slightly more than double (its linear enough in the bounds of 0-20C not too worry to much about the fact its not linear) so you would gain about 10-15C on the top temperature and still have a working system with only 4 radiator slots (a lot cheaper), but you can't put other components in that loop.

Ideally you will want full length blocks but neither of your cards are reference design which means that probably isn't an option. The problem with the generic blocks and heatsinks is the VRMs can get really hot with just stick on passive cooling. Its not really sufficient for an overclocked high end card and its easy to miss cooling something really important and blow the card up. I don't like the generic block approach, its a lot more risky and doesn't allow for the cooling of everything via water.

I'm looking to run TY-140s in push configuration as they would have the same sound profile as my CPU cooler and have decent 1.89 measured static pressure as well 70 measured CFM.
http://www.overclock.net/t/806539/thermalright-ty-140-review

As for the cooling of the VRMs, how expensive are water-blocks?
Would I be able to get away with using 2 water-blocks per card? (One for GPU, One for the large set of VRMs?)

 

[BrightCandle]

That fan is really problematic for radiator mounting. It obviously won't fit on a 120mm rad because its too big and the mounting holes won't line up on a 140mm radiator because its designed for a 120mm fan mount. That is not an appropriate fan for a radiator.

As to the vrm cooling there isn't the mounts nor the space for a second water block. It needs to be passive blocks or full cover, isn't anything in between that I know of. The heights of the components really differs and whatever you use either has to match those heights or be small enough that its mounted on individual components.

 

[24601]

According to this
http://www.swiftech.com/KOMODO-HD7900.aspx#tab3

The Sapphire 2L 7950 is a reference pcb.

The XFX Double D FX-797A-TDBC is obviously not a reference pcb.

The HIS IceQ Boost Clock H795QC3G2M is obviously not a reference pcb.

Can't find information about the SAPPHIRE 100351SR though.

 

[Kenmitch]

According to this
http://www.swiftech.com/KOMODO-HD7900.aspx#tab3

The Sapphire 2L 7950 is a reference pcb.

The XFX Double D FX-797A-TDBC is obviously not a reference pcb.

The HIS IceQ Boost Clock H795QC3G2M is obviously not a reference pcb.

Can't find information about the SAPPHIRE 100351SR though.

The saphire has the AMD logo above pci connector so should be reference design as far as i can tell.