6800GT + DangerDen NV68 Project Result

Ok, I've finally gotten all the components and parts needed to complete my 2-week long project. What I've done is install the DangerDen NV-68 waterblock on my BFG 6800 GT OC card and put it on its own water loop.

Previously, I had connected the DD NV-68 to the Koolance Exos loop which already had a waterblock for the CPU. Since the Exos uses a 1/4" ID tubing system, I had to buy 2 hose adapters to convert between 1/4" and 3/8".

Here is what it looked like:


Just as I suspected, the Exo's pump and radiator weren't enough to adequately cool both the CPU and the 6800 GT (overclocked to 435/1200MHZ). Although I didn't have to downclock my CPU or GPU, the load and idle temps were higher than before when I was using the Koolance GPU-180G waterblock just on the core.

Here are the comparison of temps (Koolance GPU-180G + CPU-200G versus DD NV-68 + CPU 200-G):

*GPU-180G: Idle = 53-55 C, Load = 66 C, Ambient: 45 C
*DD NV-68: Idle= 55-56 C, Load = 78 C, Ambient: 55 C

My CPU's idle went up too from 32-33 C to 35-36 C. CPU load went from 35-36 C to 37-38 C.

After being immensely disappointed and feeling stupid for thinking that the Exos could handle both the CPU block and the DD NV-68 block, I decided to make my own second waterloop using a more powerful pump and better radiator.

For the pump I chose the Via Aqua 1300 for its low price and 370GPH flowrate. The pump was initially very loud around 50 dba. After Googling, however, I found a guide to silence the Via 1300. Surprisingly, it worked and my pump is now the least noisy component in my setup.

For the radiator, I chose the 1986 Chevy Chevette heatercore:


I found 3/8" x 1/2" and 3/8" x 3/8" barb to FNP adapters at Home Depot and installed them to the heater core.


With all the components gathered, I set it up like this:



Here is a picture that shows the overall perspective a bit clearer:


So, how did all this work out?

*CPU idle decreased to 31-32 C and CPU load to 33-36 C.

*GPU went down to 49-51 C idle/31-33 C ambient and load temp at 60-62 C for the core and 43-44 C for load ambient.

These temp readings were made with the CPU at [email protected] and GPU at 435/1200MHZ. My room ambient is heldconstant by my windows AC unit calibrated at 72 F.

Closing comments:
(1) You shouldn't buy and install the DD NV-68 on your 6800 series card if you own a preconfigured kit like the Koolance Exos or Corsair Hydrocool system. The lowly flowrate of the pump and the small aluminum radiator cannot handle the heat that well.

(2) When installing the DD NV-68 block on to the GPU, you should use a flashlight or some other light source to make sure that the copper block is indeed touching the GDDR3 modules. The first time installed it in a hurry, I got artifacts. When I took it off, I noticed that 3 of my GDDr3 modules weren't making contact (no AS5 residue on the copper).

The second time, I really took my time and made sure all contacts were being made. I experimented with the order of screwing down the springs. The guide on the Internet was inadequate so I had to improvise a technique of my own.

I hope my experience will help someone who's also thinking about buying the DD NV-68 block. If you guys have any suggestions to make it better or just have questions, shoot them my way!

i love posts about experiments and tests, gives me an idea of what may/may not work and helps me shape future plans. i kinda figured that a high-end processor and gpu would kill a "convenient" wc setup and something a little more hardcore would be required. well, not that the exos couldn't handle it, just couldn't handle it as well as something custom.

though with the project i'm planning i probably should've just bought 2 exos systems and ran 1 to the cpu and 1 to the gpu and maybe saved some money.

Here is an update to my current setup. After bleed testing the system for leaks, I've since made some pump "foots" using foam pads cut into smaller square pieces.

To dampen the vibrations from the heatercore and fan, I've bought 1/2" x 5" felt pads from Home Depot.

Is there any air even going through your external heatercore? It looks like it's set straight down on the table and would prevent any air...

It looks like it's sitting on a few screws or something. Maybe 1/4" from the table. Looks way way too close.

Deadlierchair said:

Is there any air even going through your external heatercore? It looks like it's set straight down on the table and would prevent any air...

Click to expand...

I thought I had to raise the bottom of the heatercore at first too but it's apparently unnecessary.

Without the fan on, the GPU core is 61 C at idle. With the fan on, the core does its job and brings the idle core temp to 51 C.

With the AC on, it gets as low as 47 C.

Besides, the fan is pulling the air out so it doesn't really matter.

what was your technique to putting the NV68 on? just wondering b/c i'm about to get it and put it on my 6800gt

Gongo said:

what was your technique to putting the NV68 on? just wondering b/c i'm about to get it and put it on my 6800gt

Click to expand...

For the most part, I followed this guide.

I did a few things differently.

(1) Instead of using AS3 or AS5, I used Ceramique. I noticed that when I screw down the thumbscrews and lay the block closely against the RAM modules, some AS3 slipped off and made contact with the PCB. It caused random rebooting of my system.

Even though I used a small amount to make a thin layer, I got the same thing. So, I had to scrub the PCB using 99.9% isopropryl alcohol and Q-tips to carefully clean and dry the board.

With Ceramique, however, you don't have to worry about electrical conductivity affecting your board.

(2) When screwing down in the A-A to B-B orientation as in the above guide, I started with the lower-left thumbscrew first followed by the upper-right. I then went to upper-left then lower-right.

I did it that way because I noticed the the two GDDR3 modules on the lower-left were the most difficult modules to get in contact with the NV-68 block. I ignored the 60% compression warning because following it produced worse temps than the stock cooling.

I probably did somewhere near 90%.

After you have finished screwing down all the thumbscrews, take a look at your card from a vertical angle. If you notice that your board is slightly caved inward near the middle of the PCB where the core is, you have tighened the screws unevenly--loosen the screws and retighten so that the board is perfectly flat.

By making sure the board is perfectly horizontal and flat, I discovered I had the best contact with all GDDR3 and the core and had the lowest temps.

Currently, my temp at idle is 49 C for the core and 31 C for the ambient. This is with no AC on my door open at 2:06 pm in southern California. With stock, I had high 50's for the core and high 30's for the ambient. It got worse than the card was under load.

With the NV-68, the highest core load I've measured (using Rivatuner) is 56 C.

Good luck!

Hej good post pictures and details., but man you need to let that HC stand upright so that air flow is not obstracted. Your GPU core temps seems high to me, so I wonder what it will be with just a fan coling it?

Looks good. I also noticed with my nv68 water block that it wasnt easy to make full contact with all DDR modules. When you say it would randomly crash out of games, what exactly would it do? Would it come up with a blue screen and then shut off or? I have that problem with mine but only in certain games and it pisses me off! My card also idles at 51C in a 26C degree room at 400/1200 speeds. My 6800gt is after my 3500+ OCed to 2.6ghz so that may be bumping up the temp a little compared to if it was on a loop by itself.

Pics of my setup.

nice job man, but those temps seem a bit high still especially being on its own loop. I getting less temps running prescott overclocked to 3.9 and my gpu OC to 474/1.18 in one loop, I am using swiffy blocks tho. my idle temp is 29 CPU and 39 GPU, load is 34 cpu and 44 GPU (room temp is around 23C). maybe your GPU block needs to be remounted (I know it's a BitC#)

Prescott at 3.9 Ghz is 34 C under load, in one loop with GPU?

You either have an insane setup or your measurment is wrong.

RS said:

Prescott at 3.9 Ghz is 34 C under load, in one loop with GPU?

You either have an insane setup or your measurment is wrong.

Click to expand...

Yeah that's way too low.

Well, when using onboard temp readings its a total crap shoot to say what actual temps are. I use Motherboard monitor 5 calibrated with a rented professional temp sensor thingamajig and thats still not 100% accurate.

That 1300 pump sure gets nice and quiet when its had the impeller mod done and is on a decent pad. For under $20 its unbeatable. I tossed the suction cups. and made a faom/rubber/lucite mount for it. No more vibration noise.

well I know how the onboard temp readings are messed up, and yes that's all what I have as a way of reading temps, but I can tell you this, when I was running on air my CPU would shoot all the way to high 50s in no time running at stock speed, I then moved to watter but using a shitty aquarius II and here is my first day after moving on to a better water cooling.

Aquarius III with dual heatercore at 3.9 with stock vcore
Idle: 35C-38C
load: 46-49C

with the CPU at 4.1 with 1.536 vcore
Idle: 38C-40C
Load: 49C-52C

with my new setup (CPU and BFG 6800 U OC in one loop) at 3.9 stock vcore
Idle: 28-31
Load: 32-34

with the CPU at 4.16 with 1.536 vcore
idle: 29C-31
Load: 33-36

and finally my Gpu @ 476/1.19 (MCW50 ROCKS) I can run any 3D benching program all day long with no signs of artifact nor freezes)

Idle: 38-42
Load: 43-46


these were my temps at the first day after installing the following

Swiftech MCP650 12v DC Pump
Swiftech MCW-50
Swiftech MCW6002-P
MCW50-NV4045 (GeForce 6) Kit
HydrX Extreme Duty Coolant
Criticool Waterplant reservoir
Clearflex 1/2" ID Tubing - 15 feet
1/2" Stem to 1/2" Hose Barb Fitting
2X dual heatcore with 2 120mm fans





anf finally some overclocking shots.

3.2 @ 4.2 here

3dmark2005/cpu and gpu temps here

3dmark2003 score here


so yes, the temps might be off, but to me, with my new setup, I just could be happier ( I am talking about having the very same board and CPU and simply changing the cooling setup improved my temps by a lot as well as my OC is just what makes me happy)

I can't help but imagine all that green dyed coolant all over that awesome carpet.

carefull with all that liquid!

Nice setup.

hehehehehhehe

I would rather have it spill on my carpet than my motherboard

Guerillah.. what's the dye you used to make it so blue like that?

The tubing is blue, I got it from dangerden I have no dye in my water, only distilled water and water wetter.

RS said:

Prescott at 3.9 Ghz is 34 C under load, in one loop with GPU?

You either have an insane setup or your measurment is wrong.

Click to expand...

I guess "insane setup" is the correct answer.

I like that dual rad setup. Pretty cool.


I guess buying blue tubing is the only way to get really decent blue. All the blue dyes Ive tried either disapears over a short time or is just really light.