GTX 780 SLI with 1 reference, 1 ACX?

May 14, 2013
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I recently ordered a couple GTX 780s that are due to arrive tomorrow. Because I grabbed them as they became available (and purchased from Newegg with their no VGA return policy), I'm ending up with 2 EVGA 780 SCs - however, one has the reference cooler and the other has the ACX cooler.

From a performance standpoint, could these work effectively together if the OC potential for each card is roughly equal? My thought would be to put the reference SC in the bottom slot, venting out the back of the case, with the ACX in the hotter top slot since it appears to be a much cooler card at load. Will the reference card still likely bottleneck the ACX card significantly?

I'm not particularly experienced with configuring these sorts of setups so I'd appreciate any input I could get. I'm running a full ATX tower right now with a 230mm front intake, two 120mm side panel intakes, a 230mm top exhaust, and a 140mm back exhaust. I'm considering going to a custom loop water cooling option at some point, which would be better suited for 2 reference cards, but given the airflow, might 2 ACX cards be sufficient to get solid OCs without running into a temp wall?

Thanks in advance for any help you can offer!
 

tviceman

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Mar 25, 2008
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It will work just fine. Put the ACX on the bottom since it is open air and does not suck in air through the rear of the card. If it does not have adequate space for it's dual fans to work then it's effectiveness is significantly reduced.
 
May 14, 2013
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It will work just fine. Put the ACX on the bottom since it is open air and does not suck in air through the rear of the card. If it does not have adequate space for it's dual fans to work then it's effectiveness is significantly reduced.
Ah, I wasn't thinking about the clearance for the ACX fans. The reference cards both have intake and exhaust through the back of the card? From the tests run by TweakTown, the ACX card runs significantly cooler than the reference - won't the reference card get hot faster running in the top spot with the heat from the ACX card underneath?
 

p_monks33

Golden Member
May 22, 2011
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Definitely put the ACX in the bottom slot, the blower style card on top will pull air from the front of the card and push it out of the back, the ACX card will suck air through the bottom of the card and expel it through the sides of the PCB. If the ACX were on top it would suck heat off of the back of the other card more than if you put the reference cooled card on top.
 
May 14, 2013
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Definitely put the ACX in the bottom slot, the blower style card on top will pull air from the front of the card and push it out of the back, the ACX card will suck air through the bottom of the card and expel it through the sides of the PCB. If the ACX were on top it would suck heat off of the back of the other card more than if you put the reference cooled card on top.
Would 2 reference cards be better for SLI then? I didn't realize the reference cooler had its air intake from the front of the card as I assumed the intake was on the face of the card in a similar location to where the ACX fans are on that card.
 

p_monks33

Golden Member
May 22, 2011
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The reference design does draw some air in through the bottom of the card, the back of the card is the main inlet however, I would say, yes two reference cards will likely give you better temperatures, and they will cosmetically look the same if that is something that might bother you. How many slots are between your PCI-E slots?
 
May 14, 2013
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The reference design does draw some air in through the bottom of the card, the back of the card is the main inlet however, I would say, yes two reference cards will likely give you better temperatures, and they will cosmetically look the same if that is something that might bother you. How many slots are between your PCI-E slots?
Yeah, I would definitely prefer the cosmetics of two identical cards and I find the reference cooler much more attractive. Not to mention reference cards will give me better options if I decide to water cool eventually. I hadn't even realized that the TweakTown results showing the ACX in SLI as the much cooler card had the ACX in the bottom slot. It seems like they ran an open bench too which might be misleading but the reference card was wayyy hotter at load than the ACX.

I'm running an ASRock Z77 Extreme4 mobo. I'm pretty sure there are only 3 slots between the cards...might need to upgrade the mobo if I want to get the best results on air?
 

p_monks33

Golden Member
May 22, 2011
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Your MB has the same slot spacing as my Asrock Extreme 3 Gen 3 Z68, I wouldn't want to stack two open style coolers in my pc, I have done it before, and it really wasn't good for temperatures. Open bench is a whole separate beast from a closed case scenario.
 
May 14, 2013
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Your MB has the same slot spacing as my Asrock Extreme 3 Gen 3 Z68, I wouldn't want to stack two open style coolers in my pc, I have done it before, and it really wasn't good for temperatures. Open bench is a whole separate beast from a closed case scenario.
I wonder to what extent high CFM side case fans blowing directly on the video cards would help the temps. Seems like the case for water cooling continues to grow if a mobo replacement will be needed to take full advantage of cards.
 

Murissokah

Junior Member
Jul 25, 2013
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Sorry for the threadcromancy, but did you ever get to run the cards in SLI? I'm asking because I was planing on SLI'ing a couple blower-style GTX 970s and circumstances forced me to accept an ACX in the mix.

If anyone asked me if they would work in SLI, my answer would have been "Of course, no problem! They only have to use the same GPU." But then I saw this: https://www.evga.com/support/faq/afmviewfaq.aspx?faqid=59534

The blower card is the 04G-P4-1972-KR and the ACX version is the 04G-P4-2974-KR, for some reason EVGA states that it will not work. I can't think of a reason other than them intentionally sabotaging their user base. Or maybe they just don't want to support this Frankenstein SLI. Anyway, if I could find out whether or not it will work before the ACX card arrives I can decide whether to open it or sell it new in box. Unfortunately, I live in a country where we can't RMA stuff that is not defective.
 
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