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780ti DirectCU II x 3 cooling options beyond stock and card spacers?

mindsignals
Level 9
I'm having two issues on my new X99 system with 3 x 780ti DirectCU II cards. I'm running them in SLI although I'll need to disable SLI when using surround (probably most of the time) once my three PG278Q monitors show up (if ever).

I'm using the ASUS Rampage V Extreme motherboard in a Silverstone Fortress FT-04 case for the three cards. I've got a 5930k CPU with a Noctua D15 fan/heatsink cooler (one fan is swapped out with their smaller 120mm model so it could fit), the two built-in 240mm fans with speed control, and a 120mm exhaust fan. There are additional perforations along the rear, but no other places to mount fans as the two top bays of the FT-04 are occupied and I wanted to keep the larger 240mm twin fans which are very good.

Problem one is that the blades of the fan closest to the outer wall come in slight contact to too much contact between cards 1 and 2 and between cards 2 and 3. Card 3's fan is not adjacent anything and is perfectly fine. However, the shroud of the first two cards easily make contact stopping the fan of the adjacent card (or slightly hitting if you move the case even slightly such as when putting on the side panel or sliding the PC into position). I am using the bracket to help mount the interior of the cards in a fixed position and the sli bracket in front (tried without at first, but had no luck that way).

With the SLI bracket and rear stabilizer/bracket, I have the first and second barely avoiding contact and the second and third making the slightest of contact as of last night after working to arrange them for hours. What are others using more than one of this card (or a similar shroud) using to keep them separated enough? I noticed if I try to bring the shroud slightly in or out (exceedingly slightly so as not to bend it), the shroud will then contact the fan on that card itself (slightly pressing or lifting the shroud). The cards are mounted horizontally and stacked vertically above one another (thus why I have the rear side stabilizer attached).

Problem two is with the temperatures of the first two cards. With the fans running (without they quickly hit 99 C and throttled) the cards have hit and maintained as high as 93 - 97 for card 1, 86 - 93 for card 2, and 56 - 76 for card 3. I know this is largely attributable to the minimal space between the CPU cooler and card 2 for card 1, and between cards 1 and 3 for card 2. Card 3 is roughly in line with card 1 running solo and no adjacent card in slot 2.

Given the case's fairly minimal fan real estate, what option would likely enhance cooling particularly on cards 1 and 2 within reason of cost (say within $200) and perhaps solve the fan contact issue as well?

I do have to run three cards for three display ports with the 780ti. One other option might be to drop to two 980-series cards since the primary card supports three display ports, but I'd hate to take such a loss having bought the three 780ti's just a month ago and having just placed them into service within the past week.

One last issue is that the card in slot 2 is only being recognized as x4 although the slot shows as x8. It looks like only 16/4/8 lanes are being allocated instead of 16/8/8 (16/8/8/8) even though it is a 5930k supporting 40 lanes. Has anyone else run into this?
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8 REPLIES 8

Dr__Zchivago
Level 12
1: A little flex isn't going to hurt your video card, as long as it's only a LITTLE flex. If the fan on the heat sink is an NF-A15, then it should be 15 cm in one direction and 14 cm in the other.

You could also look at the NF-P14r

2: I use AMD, but as far as I know, you can't mix different cards in SLI - they all have to be identical models.

Z

Edit: I should've been more clear: If you have an NF-A15, 140x150x25 mm, then you should be able to rotate the fan housing on the heatsink so that you shave off 5 mm for clearance. You may have to 'engineer' your fan mounting system, though.

Thaks Dr. Zchivago. We have indeed rotated the fan a bit to the side, and had also rotated the heat sinks so that airflow runs front to back (as opposed to pushing it down on the 780ti or up toward the solid panel just above it). The first card goes right up against the heat sink (at best a millimeter or two away) although its fan faces toward the second 780ti. Those are literally no more than 1mm or less apart betwen the fan's edge and the bottom of the next card; same for the separation between cards 2 and 3.

I plan to try inserting a spacer to see if that will at least stop the fan from making contact, but am also still concerned I need to amplifly cooling above stock at least on cards 1 and 2, as a mere 15-minutes in BF4 with all eye candy had the cards at 97c, 93c, and 58c respectively during tri-sli and ultra settings. It was crushing on frame rate even at those settings to a single 1080p screen (awaiting 3 x PG278Q on backorder which is the real reason I have 3 780ti's). I know heat wouldn't be an issue with two 980s which is a potential option but I'm not sure that could drive 3 1440p 144hz monitors effectively with eye candy, and I had bought the 780ti's just over a month ago. >.< I need 3 total displayports (which is on 1+ 980s or on three 780tis collectively).

I have also not been able to figure out why it is only recognizing the second card at 4x as with this CPU (and according to lanes available in the BIOS), it should be given 8 lanes also.

mindsignals wrote:
rotated the heat sinks so that airflow runs front to back (as opposed to pushing it down on the 780ti or up toward the solid panel just above it).


It is definitely a good idea to have your case's airflow be one direction (front to back, with no direction changes), but, there is something to be said about creating eddy currents that circulate air in spaces that don't see a lot of airflow (air in the front and out the top, exclusively, for example).

mindsignals wrote:
The first card goes right up against the heat sink (at best a millimeter or two away) although its fan faces toward the second 780ti. Those are literally no more than 1mm or less apart betwen the fan's edge and the bottom of the next card; same for the separation between cards 2 and 3.

I plan to try inserting a spacer to see if that will at least stop the fan from making contact


Be careful with spacers - if it is highly insulating, then you can generate a relatively strong electric field between the heatsink and the GPU, which might cause problems (I have no data to support this, just that I know that the heat sink is less likely to be well grounded, and so could build up a static charge.

It can't be too conductive, though, or your could create a short on the back of your GPU PCB - haha. You might use a metal wire between the heat sink and case roof to 1. add support for the sink, and 2. ensure a ground for the heat sink to prevent static charge, and then insert your spacer.

Probably a bit overboard, but that's my way - haha

mindsignals wrote:
I need to amplifly cooling above stock at least on cards 1 and 2, as a mere 15-minutes in BF4 with all eye candy had the cards at 97c, 93c, and 58c respectively during tri-sli and ultra settings. It was crushing on frame rate even at those settings to a single 1080p screen (awaiting 3 x PG278Q on backorder which is the real reason I have 3 780ti's). I know heat wouldn't be an issue with two 980s which is a potential option but I'm not sure that could drive 3 1440p 144hz monitors effectively with eye candy, and I had bought the 780ti's just over a month ago. >.< I need 3 total displayports (which is on 1+ 980s or on three 780tis collectively).


What I have done - and, it actually made a difference of 10 degrees C overall - is to rig a 120 mm fan on the back of my case, sitting right at the grills where the GPUs vent out, and pulling air out of the case - blowing backwards. It has helped to draft air out of the case and through the GPU heat sinks. I also have high positive pressure inside my case, so air tends to flow out through there on its own, but the fan has helped clear out the hot air.

Dr. Z

So far, I have added minor plastic spacers on one side which stopped the contact but not the temperatures. The first card was hitting and throttling at 99 C and the second was around 95 C while the third was in the 60s.

I have since added an extra 120mm fan (secured in mid-air by wire ties...not pretty, but functional...so that it spans across the exposed ends of all three cards blowing towards the rear of the chassis. This lowered sustained peak temps by 10 C across the first two and perhaps 3 - 5 degrees across the cooler one such that the cards don't throttle and peak around 89-90, 83 - 85, and 58 - 63 respectively. Still high, but considerable improvement. We do plan to optimize it further, but it looks like I need to send one card in as my 3 x PG278Q monitors finally arrived and I found that the display port on the first 780ti doesn't work. 😞

mindsignals wrote:
So far, I have added minor plastic spacers on one side which stopped the contact but not the temperatures. The first card was hitting and throttling at 99 C and the second was around 95 C while the third was in the 60s.

I have since added an extra 120mm fan (secured in mid-air by wire ties...not pretty, but functional...so that it spans across the exposed ends of all three cards blowing towards the rear of the chassis. This lowered sustained peak temps by 10 C across the first two and perhaps 3 - 5 degrees across the cooler one such that the cards don't throttle and peak around 89-90, 83 - 85, and 58 - 63 respectively. Still high, but considerable improvement. We do plan to optimize it further, but it looks like I need to send one card in as my 3 x PG278Q monitors finally arrived and I found that the display port on the first 780ti doesn't work. 😞


1st, drop the plastic spacers and use wood instead (Thats ABC of hardware)
2nd, for temps, some of us were really in to the temp issue and what we found out was this:
there is only 2 ways to lower the unlocked cards temps:
1 - get a liquid cooling system for the cards
2 - (this is the best way to go for fans) USE GPU-Tweak for making a Fan Profile. these unlocked cards have a difference of 18c-23c UNDER LOAD between the CORE & VRM (that means, if the core is at 82c then the VRM will be 100c). what you want to do is to keep your core temp under 82, and to do that use GPU-Tweak.

here, this is mine:

ºi7-4790k, ºZ97-A, º4x4GB Ripjaws X 1600mhz, ºASUS GTX 780Ti OC [DC2OC] ºCorsair GS700, ºCM 690 IIIº LG E2241T ºWin 7 Ulti' SP1 x64

1stcowgirl wrote:
1st, drop the plastic spacers and use wood instead (Thats ABC of hardware)
2nd, for temps, some of us were really in to the temp issue and what we found out was this:
there is only 2 ways to lower the unlocked cards temps:
1 - get a liquid cooling system for the cards
2 - (this is the best way to go for fans) USE GPU-Tweak for making a Fan Profile. these unlocked cards have a difference of 18c-23c UNDER LOAD between the CORE & VRM (that means, if the core is at 82c then the VRM will be 100c). what you want to do is to keep your core temp under 82, and to do that use GPU-Tweak.

here, this is mine:



I agree with the idea of the custom fan profile, but fans will be running full-bore well before GPU temps hit 95+ and the GPUs start throttling.

My GPUs are all on water, now; but, I stand by my previous statement that you need large positive pressure inside the case, which will help force air across the GPU heat sinks, and out the back. It worked fabulously with my three 7950s (V277 - basically, downclocked 7970s), and I never saw temps like that, even under substantial overclock.

It's worth a try, at least, if nothing else has worked for you.

Z

1stcowgirl
Level 7
iv got 2 ways to handle this and an idea.

solution #1: take a small new and clean 4 pieces of wood (maybe 2-4mm), and place then between the cards (2 on the 2nd card and 2 on the 3rd card)
solution #2: get an appropriate case, somthing like the silverstone RAVEN3 _ (90 degree MOBO alignment.. so cards will be vertical)

you got X99 machine and 3 asus 780Ti _ (did you got the chance to measure your cards VRM temps under load? . . . yu'll be horrored to death).
anyway, we the users and clients, should ask for better designed MOBOs & Cases.!
ºi7-4790k, ºZ97-A, º4x4GB Ripjaws X 1600mhz, ºASUS GTX 780Ti OC [DC2OC] ºCorsair GS700, ºCM 690 IIIº LG E2241T ºWin 7 Ulti' SP1 x64

1stcowgirl
Level 7
7950 is a different animal.

with any other gpu that may be true but not with Asus 780Ti DC2OC!
we already tested all sort of configs to lower temps, AS I SAID NOTHING WORKED!!!! ONLY FAN PROFILE!
(ur asking what test..? well... backplate off on with blowing sides,
NOCTUA NF-A14 industrialPPC-3000 PWM 14cm 3000RPM on any side of the GPU
SCYTHE Typhoon 5250RPM on any side.
6 case fans of : NOCTUA NF-A12 industrialPPC-3000 PWM 12cm 3000RPM

LIKE I SAID... ITS DOING NOTHING TO THE GPU! ... dosent even tickle its balls.


to remind, we are talking ASUS 780Ti DC2OC (its design, DIGI+VRM, PHASES.. and so, are yielding this outcome).

p.s.
what the heck, ill tell you a secret, because of this card, i bouth CM 690 III, and all other fanes i mentioned above (i could easely bought custom loop with that money).
the asus 780Ti dc2oc is a nasty beast!
ºi7-4790k, ºZ97-A, º4x4GB Ripjaws X 1600mhz, ºASUS GTX 780Ti OC [DC2OC] ºCorsair GS700, ºCM 690 IIIº LG E2241T ºWin 7 Ulti' SP1 x64