7990 xfire or 780SLI

[Jacky60]

I'm building new rig, at the moment in the UK I can get 7990xfire for less than 780SLI ( £940 vs £1000). Really tempted to lay down on this as I suspect 780 will go down in price and 7990 will stay the same or go up after 290x. What should I do? Wait? I game only at 1920/1200 but will be at 1440 by Xmas. I know the 7990's are quicker and cheaper but any good reason to go 780's if I want max performance in next gen games?

 

[parvadomus]

I would buy a single HD7990. It should be enough to max a single monitor.

 

[DownTheSky]

I'll assume you'll get use these for 2 or more displays. In that case either get 7990xfire or wait for R9 290X. AMD said they'll completely fix xfire as early as the end of this year. Also we don't know just how fast R9 290X really is or how it will OC. AMD tried to keep all performance figures hidden. It might be that 2x R9 290X xfired will end up faster than 2x7990 in ultra high resolution. It also will support hardware frame pacing and other stuff. They'll also more than likely consume a lot less power and give a lot less noise even highly OCd.

If you can't wait, just get 2x7990.


Edit: I just read. 1x 7990 is enough for 1440p.

 

[Rvenger]

7990 is a killer deal right now. I'd at least pick one up.

 

[3DVagabond]

Unless you absolutely have to pull the trigger in the next 2wks., wait. 290x nda lifts on the 15th, IIRC.

I still wouldn't trust quadfire. If you have to do something sooner I recommend either 1x7990 or 2x780, if you really need that much GPU juice.

 

[Face2Face]

Unless you absolutely have to pull the trigger in the next 2wks., wait. 290x nda lifts on the 15th, IIRC.

I still wouldn't trust quadfire. If you have to do something sooner I recommend either 1x7990 or 2x780, if you really need that much GPU juice.

+ 1 - Also the amount of heat two 7990's will put out will be enough to double as a space heater.

 

[deaner]

7990 is a killer deal right now. I'd at least pick one up.

AMEN - that's what I just did - $599 after rebate!

 

[Fallen Kell]

I'll assume you'll get use these for 2 or more displays. In that case either get 7990xfire or wait for R9 290X. AMD said they'll completely fix xfire as early as the end of this year.

I'll believe that when I see it available in a beta driver release or actually released. It only took them 3 years to even acknowledge their was an issue even with just about the entire gaming/technology press saying it in every review they have done....

 

[lehtv]

AMEN - that's what I just did - $599 after rebate!

I would much rather pick two 7950's for $400 AR and OC them. Same performance and lower noise level for two thirds of the cost, and probably better resale value versus original purchase price.

The optimal solution for 1440p is two 770 4GB's for about $900... but the $500 higher cost just for no microstutter and somewhat better performance is difficult to justify. Even the 7950's have no microstutter if you run games at settings that allow constant 60fps.

 

[SolMiester]

If you stay under 25x16, you should be fine with the 7990, however greater resolution and you will start to have issues where the CF bridge cant handle the image size coming back to the primary card and hence the microstutter. It is my understanding that the MS over multi-displays on CF is due to hardware limit on the CF bridge.

 

[Enigmoid]

If you stay under 25x16, you should be fine with the 7990, however greater resolution and you will start to have issues where the CF bridge cant handle the image size coming back to the primary card and hence the microstutter. It is my understanding that the MS over multi-displays on CF is due to hardware limit on the CF bridge.

I believe Amd's current driver only works with sub 4K on DX10 and 11 games. DX 9 games such as skyrim still stutter.

 

[BrightCandle]

I believe Amd's current driver only works with sub 4K on DX10 and 11 games. DX 9 games such as skyrim still stutter.

Eyefinity/4k resolutions and DX9 are still unsupported. Supposedly they are coming sometime after their new GPU launch. If you play DX9 games (who doesn't?!) or use high resolutions I personally feel crossfire is still a bad idea. It will become less of an issue but that is the reason there is such a fire sale on these cards, they are pushing it on power limit/heat/noise and they drivers still have microstutter issues. At some point we hope it will be fixed, but it wont be this month.

 

[UNhooked]

Wasn't there a bug with 2 x 7990 where the GPU closest to the PCI bracket on the first card got crazy hott

 

[BallaTheFeared]

Stutter driver also doesn't work for more than two cards.

I would be leery of going AMD 7xxx series for CF, its not a great solution at the moment and AMD is already making changes at the hardware level with their upcoming release specifically targeted at CF issues. Which has the obvious implication that some current CF issues will never be address with current gen cards.

That said I would recommend 7950 CF for $360/$400 long before I'd recommend the $600 7990...

 

[SolMiester]

I believe Amd's current driver only works with sub 4K on DX10 and 11 games. DX 9 games such as skyrim still stutter.

Yes up to 25x16, eyefinity and 4k wont work, and the point im trying to make was, the TR report stated after a AMD conversation that the issue with the large resolutions was the 2nd GPU display data coming back over the CF bridge..In other words, Im not sure they can fix it....

 

[UNhooked]

Found it, not sure if the problem still persists.
http://www.tomshardware.com/reviews/radeon-hd-7990-crossfire-overheat,3539-3.html

 

[SolMiester]

Here's the article......

http://techreport.com/blog/25399/here-why-the-crossfire-eyefinity-4k-story-matters

multi-display CrossFire setups work differently than single-monitor ones. We noted this fact way back in our six-way Eyefinity write-up: the card-to-card link over a CrossFire bridge can only transfer images up to to four megapixels in size. Thus, a CrossFire team connected to multiple displays must pass data from the secondary card to the primary card over PCI Express. The method of compositing frames for Eyefinity is simply different. That's presumably why AMD's current frame-pacing driver can't work its magic on anything beyond a single, four-megapixel monitor.

 

[SlowSpyder]

He has two 6990's now, do you think he really notices the stutter if he's considering 7990's? I had two 5870's for a while and only one game did I notice stutter. That's not to say it doesn't exist, but not everyone notices it. OP?

 

[3DVagabond]

Nice of everyone once again digging up all of these multi monitor issues to rehash. Did any of you read the OP, though? 1920*1200 with a possible upgrade to 2560*1440. All of the multi monitor posting is off topic.

The heat and temp issues are revealing though. The 7990 uses a lot of power for a single PCB. Too much, IMO. Water is the only reasonable solution for a card like that. Just another reason why efficiency is important. Hopefully, with what should be a fairly short wait from now for 20nm, we won't have to suffer through a GTX 790, or a R9 290X*2 card.

 

[SolMiester]

Sorry 3D if it throws AMD under the bus again, however never say never...I did say it was fine for single display, and it was taken for granted it would be fixed for multi-panel....even if its 2 yrs down the line....

 

[3DVagabond]

Sorry 3D if it throws AMD under the bus again, however never say never...I did say it was fine for single display, and it was taken for granted it would be fixed for multi-panel....even if its 2 yrs down the line....

Well, I'm not willing to take anything for granted. If it's not fixed, it's not fixed and unless someone understands completely what the ramifications are, I'm not going to recommend it. What matters is the here and now. The other side of the coin though, I'm not going to paint with a broad brush and not recommend crossfire (2xGPU) for 2560*1600 or less single monitor setups because multi display still has issues. I'm certainly not going to go into a big back and forth about it in a thread where the OP has asked for advice and multi monitor is off topic.

I think a single 7990 in a case with good airflow at the resolutions the OP is contemplating is a good option @ ~$600. Not what I would go with, but nothing I can't happily recommend.

 

[Jacky60]

Unless you absolutely have to pull the trigger in the next 2wks., wait. 290x nda lifts on the 15th, IIRC.

I still wouldn't trust quadfire. If you have to do something sooner I recommend either 1x7990 or 2x780, if you really need that much GPU juice.

I've had quadfire ( two overclocked 6990's) for three years so actually I do trust it. It's not always been perfect but it's lasted incredibly well and performs in my experience exceptionally well. Yes a few annoying niggles but overall a very positive experience for me. A single 7990 isn't going to deliver much more than my current setup and that's the reason I want to upgrade. The overheating top GPU is something that concerns me though. I guess I'll wait and see, the money is burning a hole in my pocket though.

 

[3DVagabond]

I've had quadfire ( two overclocked 6990's) for three years so actually I do trust it. It's not always been perfect but it's lasted incredibly well and performs in my experience exceptionally well. Yes a few annoying niggles but overall a very positive experience for me. A single 7990 isn't going to deliver much more than my current setup and that's the reason I want to upgrade.

I'm assuming you do the "frame cap>vsync" routine? Which, don't get me wrong, is fine. Personally I always use vsync because I hate tearing and feel it smooths performance having the screen and card sync'd up. It's just hard to recommend that because most people just want to let their cards run freely with all settings maxed and brute force it.

I would be concerned with cooling the 2 cards though.

 

[Jacky60]

I've never bothered with a frame cap and only use vertical sync in BF3 mainly because in Arma 2 and Arma 3 I can't consistently get 60fps so I just turn them loose. I'm not especially sensitive to tearing but in BF3 the cards kick out around 100fps and work unnecessarily hard and hot as a result. Cooling two 7990's is my main concern atm.

 

[powruser]

The 7990 is a beast, that's for sure. The only thing that held me back from getting it versus a single 7970 was the noise levels. I really really value a quiet PC, and I watched some YouTube video comparisons of fan noise and when the 7990 ramps up it gets quite loud. Went with an Asus 7970 DirectCU II which is extremely quiet. Fan doesn't ramp past 37% while gaming.

A good option would be two 7950's. Just make sure you pick a good brand that has a decent open air cooler (most open air coolers are nice and quiet). The reference blower cards can get pretty loud.