140 Rad not enough for 6990 ?

[mauriek]

Hi guys, i need second opinion here..

I have combine gaming and a folding rig, with HD 6990, it have been running for few years with reference cooling, it's hot, normal gaming load will reach Temp 85C, with folding load it reach 100C. So i already have EK 6990 water block for few month before i have time to install it last night, but i only have EK 140 Rad. the water cooling will only for the GPU. i use 1 Xigmatek 140 fan to pull out the air. no more room for push fan because small space in casing. from my previous experience building several custom watercooling PC the 140 Rad are quite good so at first i think it will be enough to cool 6990.

after preliminary load test the idle temp is low, only around 40C but 5 minutes full load it will reach over 90C and the screen goes blank, with reference cooler sometimes it reach 103C depending on room temp but never cause blank screen. do i need bigger radiator? or something i miss?

 

[RCoon]

after preliminary load test the idle temp is low, only around 40C but 5 minutes full load it will reach over 90C and the screen goes blank,

Those are the temps with the waterblock and 140 rad? If so, then it would seem you need more rad real estate and/or a better static pressure fan. What pump are you using for this loop?

 

[mauriek]

currently i use EK DCP 4.0 pump, i have MCP355 but i think it may be overkill for this setup. yes, that is the temp with the WB and 140 Rad.

 

[RCoon]

currently i use EK DCP 4.0 pump, i have MCP355 but i think it may be overkill for this setup. yes, that is the temp with the WB and 140 Rad.

Nothing is overkill when it comes to watercooling. I'd recommend a 240 rad at least for a dual GPU card, with 2 proper static pressure fans on a high FPI rad. That and try out the MCP on the loop as well. I'm assuming you have the inlet and outlet the right way around everywhere, and you've thermal pasted the block (it sounds silly, but I have to ask).

 

[the54thvoid]

You really ought to have (as RCoon says) a 240. Best practice is a rad for each component. A 6990 is technically 2 gpu's so 2 rads (240 or 280) would be far better than a single 140. Still your temps sound way too high even for an ineffective water loop. In fact, if you only have one fan pulling air through - that's no good. You want a fan blowing external air through the rad, not pulling. If you can't arrange the case or loop in a proper fashion, I'd abandon water - it's not worth it for temps that high.

 

[mauriek]

Nothing is overkill when it comes to watercooling. I'd recommend a 240 rad at least for a dual GPU card, with 2 proper static pressure fans on a high FPI rad. That and try out the MCP on the loop as well. I'm assuming you have the inlet and outlet the right way around everywhere, and you've thermal pasted the block (it sounds silly, but I have to ask).

yeah..thermal paste are good, the rad body and fitting are all hot, it mean there's heat transfer between GPU, WB and the radiator, but it's far too hot than any normal watercooling setup i tried before.

thanks for the recommendation. i think i will try to adjust the fan pressure first by experimenting with various fan, in a few days i will try 240 rad, one of my friend broke his 240 rad by using wrong size bolt and i'm still waiting for that to return from local radiator repair shop.

You really ought to have (as RCoon says) a 240. Best practice is a rad for each component. A 6990 is technically 2 gpu's so 2 rads (240 or 280) would be far better than a single 140. Still your temps sound way too high even for an ineffective water loop. In fact, if you only have one fan pulling air through - that's no good. You want a fan blowing external air through the rad, not pulling. If you can't arrange the case or loop in a proper fashion, I'd abandon water - it's not worth it for temps that high.

i agree..it way too high, maybe change the cases to a bigger one for more fan setup flexibility.

 

[RCoon]

the rad body and fitting are all hot

Definitely sounds like the heat is being moved correctly, but it isn't being dissipated fast enough outside the case. More rad area, more fans.

 

[GhostRyder]

Well I would honestly assume a 140mm radiator would be enough for one HD 6990. I cooled two of those with a 360mm rad and a 140mm along with my overclocked processor and the temps stayed below 60. That being said I had some very thick rads so maybe depending on the thickness of your radiator it may not be enough. As stated above its probably better to move up to a bigger radiator (240mm+) and try again because if the radiator itself is getting very hot then the heat transfer is working fine your just not cooling it enough.

Though I still stand by saying its shocked me to hear thats not enough, but I never experimented with it like that so maybe for a full cover waterblock cooling that dual gpu card is not enough.

 

[OneMoar]

moar rad
moar pump
moar water
les temps

 

[razr m3]

Well I would honestly assume a 140mm radiator would be enough for one HD 6990. I cooled two of those with a 360mm rad and a 140mm along with my overclocked processor and the temps stayed below 60. That being said I had some very thick rads so maybe depending on the thickness of your radiator it may not be enough. As stated above its probably better to move up to a bigger radiator (240mm+) and try again because if the radiator itself is getting very hot then the heat transfer is working fine your just not cooling it enough.

Though I still stand by saying its shocked me to hear thats not enough, but I never experimented with it like that so maybe for a full cover waterblock cooling that dual gpu card is not enough.

General rule of thumb is a rad (120mm/140mm) per component. You had the suggested minimum and then some.

OP, the 69XX series runs pretty warm. You're going to want another radiator in that loop for good temps on the 6990. Another 140mm should do the trick or even a 240mm/280mm and then you have room to add the CPU in later!

 

[erocker]

Idk.. Shutdown after five minutes doesn't seem to be related to the radiator... I mean it can definitely happen but it shouldn't be happening in five minutes. Double check that your block is properly seated and that you're getting decent flow out of your pump. Five minutes seems like what would happen without a pump.

 

[razr m3]

Idk.. Shutdown after five minutes doesn't seem to be related to the radiator... I mean it can definitely happen but it shouldn't be happening in five minutes. Double check that your block is properly seated and that you're getting decent flow out of your pump. Five minutes seems like what would happen without a pump.

But if he's got 450W of power being dumped into a 140mm rad, isn't the system is going to heat up and reach its temperature equilibrium pretty quickly thus causing the shutdown? The rad can only dissipate so much heat from the system and I feel like at any given point the 6990 will be dumping a larger amount of heat into the system.

 

[MxPhenom 216]

Get one of those new BlackIce Nemesis 240 radiators. Or another 240 radiator but make sure its a thicker one (double thick) about 60mm. Also better fans would help, more static pressure, etc.

 

[erocker]

But if he's got 450W of power being dumped into a 140mm rad, isn't the system is going to heat up and reach its temperature equilibrium pretty quickly thus causing the shutdown? The rad can only dissipate so much heat from the system and I feel like at any given point the 6990 will be dumping a larger amount of heat into the system.

He's not cooling the entire system. 5 minutes is still way too fast.. Either way, a better radiator is in order, but flow and mounting need to be checked as well.

 

[OneMoar]

at this stage I am wondering if the card is just plain cooked from running at 100C sustained
I would be checking the thermal pads and ensuring that the VRM's are in contact with the block
else its possible that due to a combination of high load and thermal stress that the card is warped and not making proper contact with the block

 

[razr m3]

He's not cooling the entire system. 5 minutes is still way too fast.. Either way, a better radiator is in order, but flow and mounting need to be checked as well.

He's cooling the 6990 though, which is a 450W TDP card. At idle, the 140mm rad can handle the 0% load, but at 100% load it wouldn't surprise me if the loop heated up that quick.

 

[erocker]

He's cooling the 6990 though, which is a 450W TDP card. At idle, the 140mm rad can handle the 0% load, but at 100% load it wouldn't surprise me if the loop heated up that quick.

It would definitely surprise me. Unless the flow was poor or the block not mounted correctly. 6990 will eat up about 340W at most.

 

[razr m3]

It would definitely surprise me. Unless the flow was poor or the block not mounted correctly. 6990 will eat up about 340W at most.

Well that would depend on which BIOS he has that little dip switch thing set to. If it's the default one, then you're right, it's the low clocks and only 350W being pumped into the loop. OP, I would definitely check the flow of your loop and even re-set the block. Then you should add an extra rad.

OP, if you have the dip switch set to the extreme performance BIOS then I would disable it until you get another radiator for your loop. That BIOS adds 100W to the cards TDP which puts a lot more heat into your loop. Definitely still look into re-seating the block as well.

 

[mauriek]

Ok..Thanks for the discussion guys, i have re check and re install the watercooling including new thermal paste and pads for the memory, nothing change, with normal gaming load it will reach 85C and with folding/crunching/burn it will reach 90- 100C within 5-10 minutes and few minutes later the monitor goes blank and need rebooting. I change the fan with faster Corsair 140 Fan it and it can stay under 90C for about 20 minutes then it will reach over 90C and then the same, adding another Corsair fan in push-pull config will make it last a little over 30 minutes, it seem run normally (under 90C temp) if i lower the the clock but it will mean lower performance. will test it with 240 Rad this weekend.

Maybe this 6990 is hotter then other but it always like that since i bought it BNIB and run full load without problem for 24/7.
240 Rad test will be needed for comparison, or maybe the 6990 are just degrading to a point where it produce more heat output for same performance, is it possible?

 

[Aquinus]

You know, something other than the GPU itself could be overheating. Is there TIM on the DRAM and VRM modules? If there isn't any compound on them the memory or VRMs could be be overheating. I would make sure the block is getting mounted properly and is in contact with all components that need to be cooled as well as making sure that you didn't use too much compound on the GPU.

How warm is the rad getting when the GPU is loaded? warm or hot? If it's only kind of warm, water probably isn't flowing fast enough through the loop for one reason or another. Also if you keep the GPU loaded near 100*C, that is hot enough to boil water, if there isn't enough flow the water in the loop could begin to vaporize and over time those pockets of air in the loop can reduce water flow even more.

 

[mauriek]

You know, something other than the GPU itself could be overheating. Is there TIM on the DRAM and VRM modules? If there isn't any compound on them the memory or VRMs could be be overheating. I would make sure the block is getting mounted properly and is in contact with all components that need to be cooled as well as making sure that you didn't use too much compound on the GPU.

How warm is the rad getting when the GPU is loaded? warm or hot? If it's only kind of warm, water probably isn't flowing fast enough through the loop for one reason or another. Also if you keep the GPU loaded near 100*C, that is hot enough to boil water, if there isn't enough flow the water in the loop could begin to vaporize and over time those pockets of air in the loop can reduce water flow even more.

I think the VRM may contribute to the overall heat, because the area around it also hot when it touch by hand, With EK 6990 GPU Block we have to install the thermal pads on the VRM and DRAM before we mounted the block. after second installation attempt i can be sure that the block are mounted properly.

When loaded the rad is not warm, it's quite hot, hot enough to cause water vapor to accumulate in the upper part of reservoir when i fill it 2/3 or near full.

 

[bubbleawsome]

Shouldn't it be near as full as possible? Also, that rad should be able to dissipate that card to keep it under 90c. The 295x2 does only have the GPU's under water, but keeps them under 70c-ish even then. I suspect either the fan not being enough or super high ambients. (Or a clogged rad. Is it dusty?) A 140 rad should cool that.

 

[Aquinus]

I think the VRM may contribute to the overall heat, because the area around it also hot when it touch by hand, With EK 6990 GPU Block we have to install the thermal pads on the VRM and DRAM before we mounted the block. after second installation attempt i can be sure that the block are mounted properly.

When loaded the rad is not warm, it's quite hot, hot enough to cause water vapor to accumulate in the upper part of reservoir when i fill it 2/3 or near full.

The rad is hot? The fan you're using might not be powerful enough to move air through the rad if heat seems to be getting to the rad just fine. Moar airflow! Gotta dump that heat faster.

 

[OneMoar]

what are your ambient room temps ?

 

[Vario]

Get bigger fans...
Delta or Nidec