290 Crossfire Vs. 780 SLI Vs. 780Ti

[richiegore]

Elfear, what size rads are you using for the 290s, considering watercooling again but my space is limited. The krackan G10 kit seems pretty good and that's only a single rad but everyone seems to recommend a crazy amount/size of rads for water cooling...

 

[Silverforce11]

Elfear, what size rads are you using for the 290s, considering watercooling again but my space is limited. The krackan G10 kit seems pretty good and that's only a single rad but everyone seems to recommend a crazy amount/size of rads for water cooling...

Because people want 10C over ambient OR to be able to run very quiet fans, they need excessive rad surface area for that.

My 240mm AIO keeps the R290 10C over ambient while mining.

 

[McLovin42]

ok its pretty apparent this mclovin42 guy is here only to bash amd...every amd thread got shat on by him.

Well, Im sorry, but the products produced by AMD are suspect at best. What is the title to this thread? I prefer and promote absolute stability and reliability, not "fps" especially when all the cards in question don't have issues with FPS ability to begin with. But AMD cards run hot, their reference coolers are terrible, not exactly what you want if your looking for your setup to last "a long time" as the OP wants..........

 

[Elfear]

Elfear, what size rads are you using for the 290s, considering watercooling again but my space is limited. The krackan G10 kit seems pretty good and that's only a single rad but everyone seems to recommend a crazy amount/size of rads for water cooling...

I'm using a pair of Phobya G-Changer 420s although you could get away with a lot less. Like SilverForce mentioned, I wanted to have a very quiet system so I went overboard on the rad area.

 

[Pandamonia]

It's better because 400w+ is dumped outside your case with 780 Reference, whereas with 780 Lightning OC 700w is dumped inside your case and recycled through your cooling solution.


Outside of very well done case airflow 780 Reference is by far the best cooling option available, followed by reference 290. Yeah, I'd rather have two reference 290s than two aftermarket 290s. I had two TF3 7950s in an open bench and without putting a 120 on top to push down and out air from between it was a completely impractical setup.

This is exactly what Reference cards were designed for.

That would be true if it was a fact but im sure its not.

The heat coming off the back of the PCB is equally as hot as the air coming off the fins. I had 2 reference coolers before and the top card was still way hotter.

I have my cards totally open so the air can leave the case and the bottom card is 65c at FULL load! and the top card is 85-94c at the same time. So the Air in the case is not the problem its the air being heated by the back of the PCB on the card below. You only have to feel how hot it is to see whats happening.

Im going to get a new case and use the other PCI 2.0 slot to give me space. Or i might upgrade to Haswell Hex core and a new bigger motherboard.

 

[Pandamonia]

A couple of things. 1) If you can run 1200 then you don't really have too much of a heat problem. 2) If taking the side off of the case helps, your case has a problem.

Yes 🙂 but when you know 1300+ per card is there its hard to leave it on the table 🙂

Also my Lian Li was designed in an era before GPU's put out this kind of heat!

 

[richiegore]

Wow that's alot of radiator... I'd be running a 120mm rad plus a 240 or possibly 120mm plus a 280 in push pull... I think the first option would be pushing it and the second option about ok... so long as the temps stay below 70 all round at a reasonable fan speed then I'd be happy... Personally I think people go crazy on the radiators but if you have the space then why not, I'd do the same! Max temp the room will ever be is 23 degrees.... Elfear, have you had any of the black screen issues people have been talking about on overclock.net? Personally i think its related to software reading the gpu sensor data like cpuz or afterburner etc. I am a bit concerned about the issue so it would be goof to hear your experiences! Thanks everyone so far for your input!

 

[BallaTheFeared]

That would be true if it was a fact but im sure its not.

The heat coming off the back of the PCB is equally as hot as the air coming off the fins. I had 2 reference coolers before and the top card was still way hotter.

I have my cards totally open so the air can leave the case and the bottom card is 65c at FULL load! and the top card is 85-94c at the same time. So the Air in the case is not the problem its the air being heated by the back of the PCB on the card below. You only have to feel how hot it is to see whats happening.

Im going to get a new case and use the other PCI 2.0 slot to give me space. Or i might upgrade to Haswell Hex core and a new bigger motherboard.

That's because non reference designs generally push a lot of air down to the motherboard, which then comes back up into the fan because it is blocked by the back of the other card, thus a recycle effect takes place where heated air from the top card is constantly recycled over and over through the design itself.

Non reference open air cooling was never designed for stacked MGPU configurations, it performs poorly in the same conditions reference does not.

Pretty easy way to see this is to remove the mobo from your case, take a piece of cardboard about an inch thick and wedge it between the two cards to create a V between the two. Then place a 120mm fan on top of the cards towards the back blowing down at the motherboard.

You should see a 10-15C drop in temps at the same fan speed, the reason your current method of removing the side panel and using a box fan isn't working is because it isn't actually addressing the fundamental problem with non reference designs in MGPU.

 

[SolMiester]

That would be true if it was a fact but im sure its not.

The heat coming off the back of the PCB is equally as hot as the air coming off the fins. I had 2 reference coolers before and the top card was still way hotter.

I have my cards totally open so the air can leave the case and the bottom card is 65c at FULL load! and the top card is 85-94c at the same time. So the Air in the case is not the problem its the air being heated by the back of the PCB on the card below. You only have to feel how hot it is to see whats happening.

Im going to get a new case and use the other PCI 2.0 slot to give me space. Or i might upgrade to Haswell Hex core and a new bigger motherboard.

I do like the Raven cases for these instances, even if you have to put an extractor fan on the side door close to the top of the cards.....

 

[Elfear]

Elfear, have you had any of the black screen issues people have been talking about on overclock.net? Personally i think its related to software reading the gpu sensor data like cpuz or afterburner etc. I am a bit concerned about the issue so it would be goof to hear your experiences! Thanks everyone so far for your input!

I haven't had any issues with black screens like some other users have. I flashed both cards with an Asus bios though to unlock the voltage and I've heard that fixes the issue.

 

[richiegore]

That's good to hear you haven't had issues, it would be killer to setup a full loop only to have issues and have to tear it all down. I'm half thinking about getting a 780ti now and upgrading in on to two years, there is always that itch to get new technology.... That said I don't think a single gpu really cuts it if you want to stay above 60fps... Even dual gpus drop below 60fps... I wonder will mantle help reduce the periodic framerate drops.... If only direct x had mandatory triple buffering!

 

[wand3r3r]

I haven't had any issues with black screens like some other users have. I flashed both cards with an Asus bios though to unlock the voltage and I've heard that fixes the issue.

No black screens here either. In bf4 it's smooth sailing in crossfire.

 

[wand3r3r]

Pretty easy way to see this is to remove the mobo from your case, take a piece of cardboard about an inch thick and wedge it between the two cards to create a V between the two. Then place a 120mm fan on top of the cards towards the back blowing down at the motherboard.

You should see a 10-15C drop in temps at the same fan speed, the reason your current method of removing the side panel and using a box fan isn't working is because it isn't actually addressing the fundamental problem with non reference designs in MGPU.

That sounds a little scary. I had some issues testing an open bench and I thought it was likely due to the floppy nature of the cards without any support (they are very wobbly when they are just sitting on the MB). I quickly reverted back. If the connections are poor to the PCI-E slot I can't imagine good coming out of that.

 

[Z15CAM]

If you're under water and considering Price/Performance, I would by 2 x VisionTek CryoVenom R9 290 at $550 ea for CF Gaming and Mining. OUT of STOCK like everyone else but if they come back at that price it's a great deal: http://www.visiontekproducts.com/in...om-liquidcooled-series-r9-290-detail?Itemid=0

It's essentially a Reference R9 290 with an EK water block that has been Tested and Bios Tweaked to a 1175/1450 Mhz Clock. You could hardly build it yourself for that price and it has a Warranty.

 

[richiegore]

I definitely wouldn't try to wedge your graphics cards a part, that's got to cause problems with your pci sockets in the long term! I would position a 120mm fan blowing down the length of them from the right hand side as you look at them. I think blowing directly at them wont help that much it just create more turbulence, you need longitudinal airflow...

 

[richiegore]

The vision tech card looks good but only has a 2 year warranty, also at those clock speeds I think two of them would definitely overload my Corsair AX850 Gold, elfear, what psu fo you have and have you ever taken a measurement at the wall?

 

[BallaTheFeared]

Just get the better designed card if you're going MGPU, GTX 780 SLI is the only solution presented that works well out of the box and doesn't require additional modifications to justify it.

 

[omeds]

Reference 780 SLI ftw.

 

[Z15CAM]

The vision tech card looks good but only has a 2 year warranty, also at those clock speeds I think two of them would definitely overload my Corsair AX850 Gold, elfear, what psu fo you have and have you ever taken a measurement at the wall?

A Corsair AX850 Gold will max out at approx 950 Watts with 81% efficiencey before it trips. I have the same KM3 design with the XFX 850W Pro and would be confident to run either the 290 or 290X in CF at 1200Mhz for Gaming but wonder about Mining.

Luckily my rent includes the electrical bill. I'm also set up for 2560x1440p gaming. I will be running a single Gigabyte R9 290X under water come this week end - Bought it for $549 CDN before the 290 was released and before this Mining craze. If I had the insight I would have bought 2 290's at $399 CDN ea or $1100 for 2 Vision Tek CryoVenom R9 290's.

Don't peg me as an AMD FanBoy because I was in the process of ordering an EVGA GTX 780 Classy when AMD released the R9 290X for $250 cheaper and the 290 wasn't on shelf yet. I lieu of today's prices I consider myself ahead.

 

[powruser]

Reference GTX 780 SLI sounds appropriate in your situation. 780 Ti is just too expensive.

 

[Gloomy]

Pretty easy way to see this is to remove the mobo from your case, take a piece of cardboard about an inch thick and wedge it between the two cards to create a V between the two. Then place a 120mm fan on top of the cards towards the back blowing down at the motherboard.

D:

 

[Elfear]

The vision tech card looks good but only has a 2 year warranty, also at those clock speeds I think two of them would definitely overload my Corsair AX850 Gold, elfear, what psu fo you have and have you ever taken a measurement at the wall?

I use a 1050W Enermax Revo. I haven't measured power draw at the wall with both cards overclocked, but they pull ~650W while mining at 947/1250. The system with one card will pull ~500W at 1275/1450 while gaming. I would think a good quality 850-900W PSU would be fine for a pair of overclocked 290s.

 

[BallaTheFeared]

D:

Its not as bad as it sounds, you don't actually put pressure on the lanes you just direct the normal sag cards can have.

It was the only way I could keep my TF3 on top from going super inferno mode...

Aftermarket on dual slot is not ideal, go reference or water.

 

[Rezist]

Right now for the prices just get a single aftermarket 780 and OC, or a single aftermarket 290 and OC. With how difficult it will be just to get a decent 290 I'd say save the headache and get a 780.

 

[Z15CAM]

It was the only way I could keep my TF3 on top from going super inferno mode...

Oh Balla you're such a Puss. I use Tie-Downs and hang the end of the Cards from top of the casing to keep them from sagging. Even a fishing leader works providing you don't short out and ensure the case has air flow.

Solution is to go Water when you reach this point.