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2xGTX670 or 2x7970 or ..?

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July 25, 2012 11:09:15 AM

I need a 2-card SLI or Crossfire setup that will run current GPU intensive games at 1920x1080, 2xAA (preferably 4) as close as possible to 120 fps.

1920x1080 @ 120Hz
i5-2500k @ 4.5Ghz
Enermax 82+ 525W (http://www.bit-tech.net/hardware/201...400-599w-psu/6)
Case is essentially identical to this (http://www.hardwaresecrets.com/artic...ase-Review/733)

1) Budget is equivalent to $800
2) Would like minimum 2Gb on a single card (Am I right this value does not double with 2 cards?).
3) Not sure about overclocking (probably prefer not to) - air only, 5 fans, case is tidy and regularly cleaned.
4) I know about the micro-stutter and driver issues.

Basically (I think) it is between two GTX670's and two 7970's, but I cannot find a direct benchmark between them in a single article. Results seem very similar, with 5+/- variance between titles.

Finally, can I just unplug my Radeons from their PCI-E slots and stick 2 NVIDIA cards in there, install software and go?

Let me know if you need more info and thanks!

More about : 2xgtx670 2x7970

a b U Graphics card
July 25, 2012 12:08:50 PM

I second that notion, you will need to upgrade your PSU if you want to SLI/CF those cards. The AMD GPU's with the latest drivers perform a bit better than the GTX 670's. The advantage of the GTX 670 is that you will have PhysX and Adaptive VSYNC that the AMD GPU's do not have. You can get 2 EVGA GTX 670 FTW for $400 a pop and they perform a bit better than even reference GTX 680's.
a b U Graphics card
July 25, 2012 12:20:05 PM

I agree with the PSU notes above.

I assume that the 670s will be slightly cheaper than the 7970s? On many US sites the 7970 is a little more expensive, depending on the model of course.

If you were asking about resolution over 1080p, then I think the 7970 would be the very clear choice. That answer is less clear at 1920x1080 @ 120 Hz; the SLI 670 is still a reasonable option for certain games--BF3 especially. But you should take a look at the benchmarks that anandtech did in a recent article comparing the EVGA 680 classified to various other high-end cards, including the vanilla 7970, the 7970 GHz edition, and the 670. You'll see that the driver updates have actually put the 7970 and 670 pretty much on par for BF3: http://www.anandtech.com/show/6096/evga-geforce-gtx-680...

The 670s would be slightly more efficient, but I think the 7970s are still the better choice. The lead that the 670 had in some titles over the 7970 has decreased since launch because of drivers, and the 7970 has intrinsic advantages--specifically its 3 GB of VRAM and its 50% wider VRAM bus, which would be very helpful if you ever decide to go for a 2x 1080 setup, and mildly helpful as your system ages (since some very intense games do brush up against 2GB of VRAM with high AA settings now even at 1080p).
Related resources
July 25, 2012 12:48:35 PM

Is here an sli / crossfire scaling comparison?
July 25, 2012 2:34:25 PM

Thank you all for the replies (esp. motorneuron).

I am pretty much set on the 7970s now. Final questions:

1) Is non-extreme, Crossfire GPU overclocking simply a matter of a good enough PSU + the right software + keeping the temps from frying? I see some pretty sick gains on the 7970 in reviews with a 1100 clock, and it seems easy and stable to do, not sure about two cards though.

2) Care to suggest a specific model?
a b U Graphics card
July 25, 2012 2:41:19 PM

(1) Yes, OCing in SLI/Crossfire is no different from ordinary OCing, but as you say, you need to keep a closer eye than usual on power usage and thermals, since you're having twice the impact on your PSU and dumping twice as much extra heat. But an 1100 overclock is barely anything on the 7970--sort of like achieving a 4.0 GHz overclock on the 2500k or 3570k. Should be fine as long as your PSU is sufficient.

(2) specific models depend mostly on pricing, I think. If you were pushing this to the limit with OCing, then it would matter more, but I don't think it makes sense to do a huge 7970 crossfire OC; it's overkill in the vast majority of situations (and I don't think you want to do it). Tom's did do a decent guide a little while ago, though: http://www.tomshardware.com/reviews/radeon-hd-7970-over... That has a nice summary of some advantages/disadvantages on common cards.
July 25, 2012 2:55:50 PM

Thanks. Since you replied very quickly, one last one - what about the 1Gb memory difference between the 670 and 7970?

What exactly happens when a game uses up this memory? What if I want to run eg. a heavily modded Skyrim? Why does a 680 with lower memory bus and less memory perform the same or slightly better than a 7970?
a b U Graphics card
July 25, 2012 2:57:42 PM

I Think the Idea everyone was trying to give you was that the 670 was the better Idea. 2 7970 will be 1 to 5% faster but take twice the power to run... Also dont forget the amount of heat these cards will be pooring out of your PC you room will heat up fast.. For the amount of power needed and the performance that is basicly the same I would do the 670 rout but still go with what you like both will be awesome.

Thent
a b U Graphics card
July 25, 2012 2:59:16 PM

etrusk said:
Thanks. Since you replied very quickly, one last one - what about the 1Gb memory difference between the 670 and 7970?

What exactly happens when a game uses up this memory? What if I want to run eg. a heavily modded Skyrim? Why does a 680 with lower memory bus and less memory perform the same or slightly better than a 7970?



That is b/c skyrim does not use all of 2 gigs so it is fine I have all the hd mods plus like 20 others lost count and skyrim runs smooth as silk 1920x1200 on a 670.

Thent
a b U Graphics card
July 25, 2012 3:00:44 PM

Also there are reviews that have a 4 gig 680 vs a 2 gig 680 and everything maxed out it does not show much of any diffrence until you are using 3 screens and that is still not huge.

Thent
July 25, 2012 3:18:07 PM

Thanks everyone! I will now do what every buyer does - make a snap choice and then check package tracking every 5 minu... No, wait, I'm going to sleep on it and read more reviews :) 
July 25, 2012 3:21:52 PM

FYI - you'll be hard pressed to get to 120 FPS consistently with either of those setups on the highest game settings. I would say 60-90 consistently is more likely (again on the highest graphics settings).

Also, I used to run with 2 Radeon 6950s in CrossfireX and from what I recall that mobo was a CrossfireX mobo. I don't believe I could had put two Nvidia cards in SLI in that board. My current X79 board will support both SLI and CrossfireX. So I would recommend you look at the specs of your current mobo and make sure it can handle either configuration.

As a reference for the FPS I'm suggesting you can look forward to, I run 2 GTX 670s currently, with a 1kw PS, 3930K CPU, 24GB of RAM, 2 256GB SSDs, and more and it's the smoothest, most stable rig I've ever owned.
a b U Graphics card
July 25, 2012 3:45:02 PM

kalidur said:
FYI - you'll be hard pressed to get to 120 FPS consistently with either of those setups on the highest game settings. I would say 60-90 consistently is more likely (again on the highest graphics settings).


Considering you can get 80-90 fps in BF3 4xMSAA with 1075 core clock 7970 I'm nearly sure two of them could push 120 fps and above....
a b U Graphics card
July 25, 2012 3:48:27 PM

El Tigre said:
I second that notion, you will need to upgrade your PSU if you want to SLI/CF those cards. The AMD GPU's with the latest drivers perform a bit better than the GTX 670's. The advantage of the GTX 670 is that you will have PhysX and Adaptive VSYNC that the AMD GPU's do not have. You can get 2 EVGA GTX 670 FTW for $400 a pop and they perform a bit better than even reference GTX 680's.



actually physx and adaptive vsync are not advatages. Advantages are that 7970 is a lot faster overclocks better, 384 bit bus width and 3GB Vram now those are true advantages
July 25, 2012 3:52:33 PM

Guys, with this mobo (http://www.asus.com/Motherboards/I [...] P8P67_PRO/) and 2 x GTX670s am I going to need a bridge? If yes, can I use my Crossfire bridge?

I promise I googled this and answers are divided...
July 25, 2012 3:53:09 PM

etrusk said:
@Kalidur

I know, but I am willing to sacrifice some bells and whistles if I can actually perceive the fabled 60Hz / 120Hz difference :) 

Here is my mobo, I believe it should be fine: http://www.asus.com/Motherboards/Intel_Socket_1155/P8P6...


Yep, that mobo should be fine with either SLI or CrossfireX.
a b U Graphics card
July 25, 2012 3:54:20 PM

joedjnpc said:
Considering you can get 80-90 fps in BF3 4xMSAA with 1075 core clock 7970 I'm nearly sure two of them could push 120 fps and above....



That is true my 7970's keep 120 fps in bf3 more consistently overall vs my 680's. The only advantage the 680's have over the 7970 is that they eats less power. I uses my 680's for 3d setup only, which i enjoy quite a bit. Once you start overclocking both setups the 7970 pulls away quite a bit since they scale better yielding better result, ie for a gtx 670 to compete with a 7950 clocked a 1200mhz the 670 would have to be clock at 1300mhz.
July 25, 2012 3:55:04 PM

etrusk said:
Guys, with this mobo (http://www.asus.com/Motherboards/I [...] P8P67_PRO/) and 2 x GTX670s am I going to need a bridge? If yes, can I use my Crossfire bridge?

I promise I googled this and answers are divided...


As a general rule, if the mobo supports SLI it will come with the SLI bridge. The CrossfireX bridge comes with the graphics card. The two bridges are not interchangeable.
a b U Graphics card
July 25, 2012 3:55:53 PM

thently said:
Also there are reviews that have a 4 gig 680 vs a 2 gig 680 and everything maxed out it does not show much of any diffrence until you are using 3 screens and that is still not huge.

Thent



the gtx 680 and 670 is more limited by it bus width not so much its vram that is why
July 26, 2012 6:20:31 AM

@BigMack
Yes, am aware, new PSU will be coming.

I don't want to push the cards with any extreme overclocks, but if there is a significant gain for a low risk then it would be stupid not to do it.

Anyhow, I went with 2 of these GTX670s > http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Reasons:
1) http://www.tomshardware.com/reviews/gaming-graphics-car...
2) http://www.tomshardware.com/reviews/geforce-gtx-670-tes...
3) Price - I would get the Zotac AMP! but it is significantly more expensive where I am.
4) http://www.xbitlabs.com/articles/graphics/display/gigab...

"Interestingly, our monitoring utilities both reported a peak GPU clock rate of 1189 MHz, although the specified boost frequency is 1058 MHz. Indeed, judging by the frame rate in Aliens vs. Predator (2010), the graphics card was somewhat faster than if it had been clocked at 1058 MHz. Moreover, we managed to overclock the GPU by 120 MHz to 1100 MHz without changing its voltage! That’s an excellent result, especially as the boost clock rate was as high as 1310 MHz at some point. The graphics memory was stable at 7568 MHz (+30%):"

5) After 3 years of AMD, I feel it would be good to jump over to the other side to have a personal comparison of quality of service, patching etc.

Thanks for all your help.
!