Topic: TriFire water cooling (was: Squeezing 2-slot cards into a single slot) - page 3. (Read 10588 times)

mysel i just use Koolance HX-CU1320VS Quads
$70 so its cheep.
and i throw on Scythe Ultra Kaze 120MM 38MM Fans
its in another room so don't care about noise.

The radiator OP has gets better cooling capacity at lower fan speeds.  That radiator you linked to is nice and "dense" but high fin density means you need much higher air pressure to properly cool it.  That means faster, louder fans. 

My current rig is almost quiet but wasn't designed to handle 3x5970.  I want to expand that to 4x5970.  I am considering putting the radiator outside and "your" radiator would be nice for that (who cares about the increased noise) however if that doesn't work and I need to keep it inside I would rather like a the larger higher c/w radiator the OP got as it can be cooled with very low speed fans.

All about the right tool for the job. 

nice rad...
but for monster rad here is a nice one
http://www.frozencpu.com/products/14193/ex-rad-141/MagiCool_Limited_Edition_Monsta_420360_Triple_120mm_140mm_Xtreme_Performance_Radiator.html
just to bad its only a tripple and not a quad. LOL

Yeah the other colored caps are for "drinking water" and "filtered water" but they are junk.  Purple cap (and it is usually a whole $0.10 more per gallon) is the distilled.

Surprisingly good stuff.  Ultra low total dissolved solids.  Lots of people use it for aquariums because it is good quality and low price.   If you have any left over it makes great coffee because it has absolutely no taste.


Have fun and be sure to give us some photos once you get i running.

Hah, yeah, 'Great Value' indeed.  I was a bit worried that it'd be crap honestly, but I figured if I started to see a lot of mineral deposit I'd flush it all and double-distill my own.  Good to know it's not just a fancy label.

I modified the side panel of my case to mount the radiator last night, and it was total fail.  Whole rig toppled over on it's side as soon as I let go  

I'm guessing it's going to be somewhere around 10lbs or so once it's full of water and all the fans are attached, so off to the hardware store I go to rig a radiator stand.

I noticed you got Walmart water.

Purple cap = solid.

Same stuff I always use.  Works great and is cheap. 

PS I am jealous of that radiator although now w/ winter temps my 4x140 is doing fine.  By next summer I am going to need a bigger or second radiator though.

Hooray for the interwebs, everything I need to water cool delivered to my door:




Here's a shot to show just how ridiculously huge the radiator is:




After much fighting with the DVI header on my scrap card, I've decided it's not worthwhile to risk the 6950s.  I managed to get it detached, but it was not pretty at all, and I'm fairly sure I damaged a couple of the traces in the process.

Instead I think I'll be going tri-fire instead of quad, trading my mobo for another with the 16x slots in a better arrangement, and selling off my spare 6950 to pick up the new mobo + 3rd water block.

i'm prety sure that a small set of wire cutters will easily cut through the header.
however my experience with soldering is that great so that is why i thought of it.

Might be a little tough - the pins holding the header in place are pretty beefy, and the header is flush with the board.  I suppose if I were an expert with a dremel/rotary tool I could hack it off.  Desoldering seems like the best bet still assuming i can melt the joint without melting the PCB

you could just cut the pins. not like you will be sending the card back for RMA or reselling the card in teh near future

Desolder fail.

I attempted to pull the DVI header off an old nVidia 7800 - while I had success wicking up all the DVI pins, the larger through-hole pins that hold the header in place would not budge.

Doesn't look like I'll be squeezing these into a single slot unless I can figure out a better way to remove the DVI block.

/sigh

[edit] After doing a bit of research, it seems my iron was just turned down too low for ROHS/lead-free solder, so I'm going to give this another shot on the nVidia card.  Also going to pick up one of those desoldering vac pumps to try to simplify things, solder wick just wasn't cutting it for me. 

I'll try to post some pics if I manage to get it detached without completely botching things

In theory but water is such an efficient cooler than even ~4 gpm is sufficient to transfer 1000W thermal load.  Remember temp is the difference between thermal energy in - thermal energy out.  If the water can remove all the thermal energy then temp will never rise above ambient.  However no radiator is perfectly efficient and that becomes the bottleneck not water flow.

Even entry level pumps is capable of 100+ gallons per minute.  It only takes ~4 gpm to remove 1000W of heat so water flow beyond a critical threshold is pretty much meaningless.  Lots of reviews that confirm this.  

There is ONE caveat.  If water flow drops low enough the stream will become laminar rathe than chaotic.  This was more a problem 10 years ago when watercooling wasn't as well designed.  Today waterblocks are designed to keep flow chaotic even at low flow rates (down to even 1gpm) thus cooling performance doesn't suffer.  If you ever get enough restriction that waterflow drops below the laminar threshold you will know.  It will be hard to keep cards cool at idle.  Cooling performance will fall off a cliff (I mean like a 90% reduction in c/w).

One last thing 100W thermal load doesn't mean 1000W at the wall.  Lets look at my system.  3x5970 & i5-2500K.  Pulls about 960W AC (at the wall) at peak.  However backing out PSU inefficiency that is about 844W DC load.  Now fans, HDD, memory, motherboard, and CPU pull about 150W so the GPU are "only" pulling ~700W.  1 gpm can transfer ~262W with <1 deg C rise in temp.  So assuming radiator could dump all that heat it would only require a flow of 2.6gpm to keep temp rise <1 deg C.  Of course the radiator isn't that good (4x120mm w/ 1200RPM fans to keep noise down) so the Delta-T is closer to 5C.

I honestly don't expect it to make much of a difference - if MadHacker's got 6 blocks in parallel and he's getting good temps, my eventual 4 cards should be more than fine.  As for the semantics..

Consider the specific heat of water -  about 4 joules/gram °C - or how much energy is required to raise the temp of 1 gram of water by 1C.  We'll take an example of 4 cards where each card is able to transfer exactly that 4 joules to a gram of water flowing through at 1gpm:

- In series, flow at 1gpm through all 4 cards, 30C water exits the loop at 34C, as each card has provided 4 joules or 1C.

- In parallel, with flow at 1/4gpm through each card, each raises the temp 4C (by providing 16 joules) - still the 30C water exits the loop at 34C.

So with the same overall flow rate through the loop, the water is raised by the same total temperature regardless of whether it's series or parallel.  

However, in the series example, the the last card gets warmer water - consistently 3C higher than the first card.  In parallel, each card gets the same incoming 30C water, so temperatures should be the same across all cards.

Additionally, in series each water block drops the overall pressure, meaning the pump must work harder to maintain 1gpm.  In parallel, the pressure drop should be roughly the same as just one block, perhaps even less if the total channel width through the blocks is more than the width of the tubing.  The pump doesn't need to work as hard.

So all together, parallel seems like the better plan - more even temps on each card, and a smaller overall pressure drop.

[edit] And I realize now I've just reiterated DeathAndTaxes' last post.. lmao.  Anyway as long as the flow decrease through the cards in parallel isn't so great that the water simply can't absorb any more heat, the cards should not 'run hotter' in parallel.

I'd be more worried of the loss of turbulence on the blocks themselves because when you split your pressure with 4 cards in parallel, you're losing all that pressure. Fluid dynamics brah. The closer a moving fluid is to a solid object, the slower it moves, and slower moving fluid = less cooler fluid over the hot block pins over a period of time = hotter gpu

If each GPU caused a 1 deg rise in water temp then the inlet temp on GPU4 would be 3 deg higher.  It likely doesn't matter because water is such an effective heat transfer fluid that all the water in entire loop is within 1 to 4 degrees of water anywhere else in the loop.

Still parallel is considered a better approach.  Also with your layout you have 6 right turns.  Ever 90 turn is roughly equal to another 2 feet of tubing in terms of the resistance it creates.  Once again pumps today are so powerful and min effective flow rates so low it is likely academic but generally a parallel approach w/ minimum number of 90deg turns is the best.

Ḃecause then gpu 4 will only get warm fluid, and run much hotter than the rest.

I did a *lot* of reading and research last night, the consensus seems to be that it doesn't matter too much, but parallel flow through the gpu array improves overall flow rates through any other blocks in your system,  usually the CPU.

Why not like this?


      IN   
       |       
       -->------- (gpu1)
              |
       --<------- (gpu2)
       |     
       -->------- (gpu3)
              |
       --<------- (gpu4)
       |     
      OUT

Just ordered all the parts to start this up, thanks for all the tips guys

I am pretty sure Bonkers was a troll from SomethingAwful, but he/she sure succeeded in getting some people worked up in very short order.