Bitcoin Forum

Ever sense I water cooled my first computer, I've water cooled every computer sense.  My ATI5970s were going to be no exception, and then, we hit the $3 mark.
After noticing how hot the back plate got I came up with this.
http://img824.imageshack.us/img824/2161/p9090238.jpg
The tools you'll need, are a dremel, drill, sharpy, sand paper and screw driver(for taking the back plate off).  As for the parts, you'll need a sheet of copper,http://www.onlinemetals.com (http://www.onlinemetals.com)
PVC pipe caps, epoxy, thermal pads and copper pipe.
Take off the back plate and use it a template.  I used an SOS pad to clean it off.
http://img52.imageshack.us/img52/5513/p9060226.jpghttp://img403.imageshack.us/img403/7818/p9070230.jpg
Drill the holes in the caps, cut the pipes to length, sand the pipes to remove dirt and oil.  Then glue everything together.  I found it easier to glue the intake and outtake first. 
I put the middle pipe in then clamped the caps to a board, then glued it in place.  Clamping them helps make sure they're level with each other. 
To get a stronger bond I scuffed up the copper sheet before I glued it in place.
http://img23.imageshack.us/img23/7185/p9090237.jpg
Cover the back of your card with thermal pads.  You'll want to use 6-8mm pads, if they're to thin contacts can poke through.  I covered more of the board, but that picture didn't come out.

http://img651.imageshack.us/img651/8656/p9090246.jpg http://img842.imageshack.us/img842/4377/p9080233.jpg
For my radiator I took a 25ft soft copper pipe and coiled it on a box fan.

http://img256.imageshack.us/img256/3444/grapha.jpg
All for about $40 to make the water block.  Once I get some pci-e extenders I'm gong to make another this time I wont cut out over the GPUs, hopefully that will get me a few
degrees cooler.  I'm also thinking about a better radiator.  Unfortunately one of my cards is having fan issues.  I've got a water block on the way, if I'm in the mood I'll do a comparison.

I'm not above begging for money, so if you want to throw something my way I'd appreciate it.  If you don't I'd be happy to know if it helped you out just the same.
1MrCoinvNxc7cjhEyVtA1UGGK9oYgLiVFs

Why the waterblock on the backside of the card?

Wow, that's pretty damned awesome!  Good work man!  I am jealous!

How did you cut the copper backplate?

How are you affixing the copper plate to the back of the card?

I am toying around with the idea of dismantling the heat sink, and putting the caps on the top of the card.  The biggest reason for it being on the back is, its easier to make.  If your card is still under warranty, and you need to send it back, all you have to do is put the original back plate on.
I used my dremel to cut the copper plate(reinforced cutoff disks are worth the extra money). When I made the template, I marked the holes for the screws, and used a small drill bit to make the holes.  I used the original screws to mount it on.
You can get the copper plate cut to the size you want.  It's about $50 for a 4x12 sheet and $107 for 12x12, so it works out to about $15-20 cheaper if you cut it yourself.

I miss these set ups.  So fun to read the hack n wack experiences

that is a wickid mod.
i use 3/8" pipe on my 5770, but it doesn't put out that much heat.
http://inlinethumb37.webshots.com/39204/2844673480106201080S600x600Q85.jpg (http://entertainment.webshots.com/photo/2844673480106201080EDfEEm)
i may do something with PVC pipe caps to watercool my 5830's

how thick copper sheet did you use?
I use 16ga or 0.647" thick.

I used .125" I would recommend .25", if you tighten the screws to tight the copper will bow a little.

Cooling the back of the PCB through thick pads seems dubious, especially when still using the stock cooler too. The thermal resistance between the components that actually generate heat and the water block is too high which would create a big temperature delta. If you have 25 degree water, you'd probably have a 35 degree copper plate, 45 degrees after the thermal pads, a 55 degree PCB, and 75 degree components still.

What you would want to do is get a real engineered water block for each of the GPU chips to replace the stock cooler. The GPU die is where 85% of the heat comes from. Inside real water blocks, it looks like a mini-radiator with fins or pins for excellent heat transfer characteristics directly from the die to the coolant:

http://www.xbitlabs.com/cms/include/image.php?src=/images/coolers/antec-kuhler-620/16_h2o_wb_big.jpg&width=350&height=236&cache=1&quality=100&aspect=0&format=

For a cheaper and better radiator, you can get a wrecking yard transmission cooler or oil cooler, it will transfer heat and return the water to ambient temperature much better than copper pipe, and unlike using a car radiator, you don't have a radiator cap & bottle outlet to leak or need big hoses:
http://ecx.images-amazon.com/images/I/413xmxki3ML._SL500_AA300_.jpg

Of course none of this is necessary, people here have multiple GPUs per system in multiple systems running on air and stock coolers.

I take it you've never used a 5970 before, then?  The rear plate, even on water, gets ridiculously hot.  The thermal design of the 5970 (and 6990) is absolutely atrocious.  I'm sure it's born out of necessity, but it doesn't make it any less craptacular.  These cards absolutely need all the cooling they can get.

While it gets "hot" (everything is relative) the GPU cores on the front is what dumps 90% of the heat.  The back may be hot but you can touch it.  If you tried to touch the heatsink on the front you would be leaving some skin behind and that is w/ fan running.  Without a fan it would cook the CPU within seconds at full load.  The VRM (also hot) are also only on the front.  The heat on the back is simply from RAM which can be reduced somewhat by downclocking the RAM.

Granted I didn't build by own but a proper waterblock can keep GPU temps @ <50C under full load and more importantly keep VRM cool too (which is usually what limits performance and creates instabilities) and that is with a fans on the radiator running at only 1200RPM (quiter than a desk fan).  My radiator is likely overloaded because it wasn't designed to cool 3x5970 so performance would probably be even better with a larger radiator.

With proper waterblock the thermal design of the 5970 is awesome.  The problem with the card has more to do w/ poor heatsink design (it doesn't cover the VRMs) than any issue on the card itself. 

I've been building water cooled rigs for almost a decade, I'm pretty familiar with how they work.  Long before watercooling was the "in" thing to do or even in the mainstream.  I wrote a research paper on it for my third college degree back in hmm... like 2000 or 2001 maybe?  I have a good working knowledge of the whole setup. 

Regardless of how much heat is output at the GPU die, be it 10%, 50% or 90%, if the temps of the other components exceed a thermal threshold, they are going to fail.  You seem to understand this to a degree with your comments re the VRMs on the 5970.  Modern CPU and GPUs do not cook in "seconds," they cook virtually instantly if they have max current applied without a heatsink applied.  They also make a nice popping sound if they don't have a heat spreader.  You might get "seconds" out of a modern CPU with a heatspreader, though.  But I digress.

The heat on the back of the 5970's are most definitely not "only from the RAM."  Try down clocking your 5970 to 300 MHz for the RAM and crank your 5970 up on both cores and tell me your ram is getting that hot. Then, tell me why exactly, the hotspots are curiously not over the RAM locations.  If you don't want to waste your time, I will tell you:

The thermal design of the 5970 is atrocious.  It gets so hot, and the HSF is so underequipped/improperly designed that you have a metric bucketload of heat bleed through from the GPU cores an the VRMs.  This is very, very bad and indicative of poor design.  In an ideal world, you should never have bleed through from the top of your PCB to the back in any meaningful amount; with the 5970, the bleed through is so bad they ship it with a token heat spreader.  ON THE BACK!  Some of that is for the ram, yes, but not entirely.  If they just needed to cool the ram, they could handle that in other, more efficient ways than a flat, quasi heat spreader that may or may not contact the chips.

I have a meeting to get to, but I'll be happy to debate the finer points of water cooling when I'm done. :)

That is simply because the primary heatsink is not strong enough to handle the thermal load effectively.  Of course via conduction heat will spread to the other side of the card.  The heatsink on the bad of the card is only warm to the touch on my waterblocked GPUs and that is just from the RAM.  On a single sided cards there is no appreciable heat on the backside of the card.

Obviously you can cool a card indirectly from the backside.  Some of the heat from GPU & VRM will leak through but it is more effective to cool it at the heat source.

Cooling the back of the PCB is the most inefficient way to cool the card.
You need to cool the heat source.
 
And yes, i dont need 10 years of building watercooled rigs to know this

Who the hell said it was the most efficient way of handling it?  Where did that even come into the equation? 

I'm a little confused on what you two are debating about at this point, if it's not the merit of the above DIY project to cool a stock 5970's for a few bucks? 

If you're talking about the most efficient way of cooling a 5970, you are dreaming if you think a waterblock will do it.  You need an LN2 EP and the associated support hardware, seal it up around the two GPUs and go to town.  I wasn't aware we were talking about how to best cool a 5970.  In anycase, the above method will get your GPUs down to about ~ -40 or 50c under full load (actually, I'm not sure about that, it might be as high as 0C given the heat those thing generate, but it will be completely depending on your LN2 cycling system).

The hardest thing you're going to have to overcome is the condensation frying or at best corroding the surrounding components depending on the ambient environment. 

back to the mod the OP posted
I'm thinking to WC my 5830's using a better system that the 5770 waterblock i have posted above.
your PVC caps are a great idea, but now I'm thinking of using copper caps instead.
that way i can solder them on and not worry about the epoxy ever letting go.

this way I can get a greater surface area on the GPU.
just not sure how much heat it will disipate on a flat copper surface...
will need to add somethign for turbulance.

I find with all the solder welds i have done. if it doesn't leak at first... it won't
I have a car RAD however it isn't copper its aluminum. (was thinking of just getting rid of them)
but with these blocks i make i won't care if they get corroded after a couple years... they won't be running that long anyways.,
some antifreeze should minimize the corrosion some.

I love the DIY coil but if you can get your hands on one some baseboard from hot water heat or a small automotive radiator would work even better

The chart is showing how hot the card is. I've used epoxy when making my reservoir for most of my builds and have never had any leaks.  To get more surface aria solder some copper screws and use a 90 degree elbow to force the water threw them.
I wasn't thinking about an oil cooler, I think I'll run down the the junk yard a pick something up.  For my next water block I'm going to make it out of the heat sink from the card with a bad fan.
To make soldering large arias or if you don't have a torch, is use the stove top.  To make a more secure soldering bond don't overheat the copper or burn the flux.

You're the one being confused. You're the one bragging about 10 yrs of watercooling experience which has no merits here.

Let me make it easier for you

1) 40 bucks isnt a few bucks
2) By efficiency, i mean with the same cost. I dont think you understand the word "efficiency" if you dont keep other variables constant. LN2? LOL good job

So yes, tell me if i'm wrong

Yes, tell me how I am wrong.  $40 is a few bucks.  This is a home brew DIY project and it's pretty nifty.  It would be absolutely idiotic to remove the stock HSF and try to fashion a WB that worked attached directly to the GPU's out of the materials here, along with the cost involved. 

Believe it or not, some people like to make things for the sake of making things.

The only confusion here is you thinking you have something to contribute to this conversation other than crapping on someones work.