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Crossfire of Sapphire HD 7870 2GB OC GHZ Dual Fan

Last response: in Graphics & Displays
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July 24, 2013 3:51:10 AM

Hi! I had just bought Sapphire HD 7870 2GB OC GHZ Dual Fan for my pc and its...AMAZING!

I was (and still) amazed by the performance of that card. Never before in my life I could play games with more than 35fps (in ultra settings)!

Alright, now is the answer. Since my mobo has the capability of dual graphic cards (another surprise to me), i had been dreaming of doing a crossfire with it later. Now the question is,

Will doing crossfire the Sapphire HD 7870 2GB OC GHZ Dual Fan give huge leap in performance?

Can I crossfire with other AMD graphic card?

That's it. Thanks for reading this!
July 24, 2013 4:12:33 AM

no, crossfire is no good, it has been long believed, and now proven with new testing methods, that crossfire does not give the same performance increase that FRAPS records in benchmarking. Uneven spacing between frames, dropped frames, runt frames, all contribute to a perceivable frame rate at the monitor that is often no better than a single card, and sometimes the stuttering added by the secont card can make things worse than a single card. The stuttering is something that has been known for a long time, and new testing methods confirm this. AMD is expected to have a driver update to fix, or at least improve these problems. Wait until someone confirms this fix in the next driver release before you go crossfire. To add to this, what is your CPU and motherboard? if your cpu bottlenecked you may get no real performance increase anyway, and a 4x slot on your motherboard can increase stuttering due to even more uneven rendering speed between cards created by the slower slot, causing more stuttering.
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July 24, 2013 4:30:26 AM

I have CF with two Sapphire dual fan 7870s. First off, what motherboard, psu, and cpu do you have?

So as crowe said there has been talk about frame time so I was worried about getting it. Once I did I noticed no difference in smoothness vs one card. CSGO feels exactly the same as with one card, except I had to set fps_max 200. There is a roughly double fps in most games, sleeping dogs had about a 105% increase in min frames. How many of those increased frames are runt frames though I can't say, but what I can say is everthing feels perfectly smooth and that is what really matters. I play at 2560x1440 and can max every game, minus AA which is barely needed at this res anyway.

I have tried playing a game at max with CF which will be very smooth and again with CF disabled and it becomes unplayable so CF does make a huge difference.

My point is take all the negative reviews of crossfire with a grain of salt. It has worked out very well for me. Maybe you will notice the "stuttering", maybe you won't. I can't say for sure.
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July 24, 2013 4:55:24 AM

wanderer11 said:
I have CF with two Sapphire dual fan 7870s. First off, what motherboard, psu, and cpu do you have?

So as crowe said there has been talk about frame time so I was worried about getting it. Once I did I noticed no difference in smoothness vs one card. CSGO feels exactly the same as with one card, except I had to set fps_max 200. There is a roughly double fps in most games, sleeping dogs had about a 105% increase in min frames. How many of those increased frames are runt frames though I can't say, but what I can say is everthing feels perfectly smooth and that is what really matters. I play at 2560x1440 and can max every game, minus AA which is barely needed at this res anyway.

I have tried playing a game at max with CF which will be very smooth and again with CF disabled and it becomes unplayable so CF does make a huge difference.

My point is take all the negative reviews of crossfire with a grain of salt. It has worked out very well for me. Maybe you will notice the "stuttering", maybe you won't. I can't say for sure.


I agree somewhat with the negative reviews of Crossfire. People are more likely to complain about issues then complement the fact that they have no issues. Provided your PSU and CPU can handle it, as well as your case, I really don't see much of an issue. It'll work awesomely for well coded games such as BF3 (graphically I mean, scaling is near 100% for most cards in SLI/CF).

If you're worried about frame latency, a fix for it is coming out July 31st. PcPer released a video showing the difference between 13.5 and the prototype driver on the 7990 -- it was giganticly different in smoothness.

you can also factor in, if you find a game in which CF has a bug, you can turn it off temporarily for a game. I've used CF and SLI (SLI with dual 670's), and SLI is definitely superior, but it really depends on what you play.
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July 24, 2013 5:16:38 AM

wanderer11 said:
I have CF with two Sapphire dual fan 7870s. First off, what motherboard, psu, and cpu do you have?

So as crowe said there has been talk about frame time so I was worried about getting it. Once I did I noticed no difference in smoothness vs one card. CSGO feels exactly the same as with one card, except I had to set fps_max 200. There is a roughly double fps in most games, sleeping dogs had about a 105% increase in min frames. How many of those increased frames are runt frames though I can't say, but what I can say is everthing feels perfectly smooth and that is what really matters. I play at 2560x1440 and can max every game, minus AA which is barely needed at this res anyway.

I have tried playing a game at max with CF which will be very smooth and again with CF disabled and it becomes unplayable so CF does make a huge difference.

My point is take all the negative reviews of crossfire with a grain of salt. It has worked out very well for me. Maybe you will notice the "stuttering", maybe you won't. I can't say for sure.


my cpu is intel core i5 4430,
the mobo is Gigabyte socket 1150 B85M-D3H
the psu is AcBel 510watt (i know, this need to be changed if go for crossfire.

wait, i don't quite understand. first you said "Once I did I noticed no difference in smoothness vs one card". then at the end you put it "How many of those increased frames are runt frames though I can't say, but what I can say is everthing feels perfectly smooth and that is what really matters". I am getting confused :??: 



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July 24, 2013 5:30:48 AM

iam2thecrowe said:
no, crossfire is no good, it has been long believed, and now proven with new testing methods, that crossfire does not give the same performance increase that FRAPS records in benchmarking. Uneven spacing between frames, dropped frames, runt frames, all contribute to a perceivable frame rate at the monitor that is often no better than a single card, and sometimes the stuttering added by the secont card can make things worse than a single card. The stuttering is something that has been known for a long time, and new testing methods confirm this. AMD is expected to have a driver update to fix, or at least improve these problems. Wait until someone confirms this fix in the next driver release before you go crossfire. To add to this, what is your CPU and motherboard? if your cpu bottlenecked you may get no real performance increase anyway, and a 4x slot on your motherboard can increase stuttering due to even more uneven rendering speed between cards created by the slower slot, causing more stuttering.


hmmm that's troublesome. but here in this one review it shows that with crossfire we can get almost the double frames as the first one. that's what had been enticing me. :lol: 

http://www.tweaktown.com/articles/4597/amd_radeon_hd_78...
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July 24, 2013 5:53:10 AM

Your mobo supports crossfire but will only run the second GPU in a bandwidth speed of X4 instead of X8 or X16. Your card is a "newer" card that will probably need at least x8 speed for optimal performance. You may experience a bottleneck on the second PCIe if you go crossfire.

Better stick to a single GPU for now.

Also the motherboard is a micro-ATX so if you have a small case you should also be aware of limited heatflow in the case and that will definitely worsen with two close-mounted 7870 ;) 
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July 24, 2013 6:13:02 AM

Mahisse said:
Your mobo supports crossfire but will only run the second GPU in a bandwidth speed of X4 instead of X8 or X16. Your card is a "newer" card that will probably need at least x8 speed for optimal performance. You may experience a bottleneck on the second PCIe if you go crossfire.

Better stick to a single GPU for now.

Also the motherboard is a micro-ATX so if you have a small case you should also be aware of limited heatflow in the case and that will definitely worsen with two close-mounted 7870 ;) 


my casing is quite large. i think the heatflow will be okay. if worse, just open the side casing! :lol: 

however, can you explain to me about the bandwidth speed of 4X, 8X and 16X? what are those things? how do you know my mobo wont support 8X or 16X? i want to learn something new here.
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July 24, 2013 6:22:26 AM

Sorry if I made that unclear. What I meant is with the fps reported by FRAPS I don't know how many were runt frames so the number is most likely an overexaggeration of the actual fps.

As far as pcie bandwidth goes the rule of thumb is x8/x8 at least for CF/SLI. An x4 slot will reduce the overall performance. x4/x8/16 is basically how much data can be pushed through the pcie slot. More is better, of course.
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Best solution

July 24, 2013 6:30:06 AM

Your motherboard's expansion slots specifications according to Gigabyte's website:

1 x PCI Express x16 slot, running at x16 (PCIEX16)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.
(The PCIEX16 slot conforms to PCI Express 3.0 standard.)
1 x PCI Express x16 slot, running at x4 (PCIEX4)
2 x PCI slots

So in english:
You have two PCIe x16 slots (Notice x16 slots is different from the speed x16. Here it means number of lanes. Very confusing;))
The primary slot is running with a bandwidth speed of x16 and the secondary is only running with a bandwith speed of x4. Actually I'm not into the technical terms of why this is but it has something to do with the motherboard not having automatic switches.

You can read more on it in this article:
http://www.tomshardware.com/reviews/pci-express-scaling...

Higher end motherboards have the ability to share the primary PCIe slot bandwidth with the second slot so they both become x8/x8 speed, which is minimum requirements for most of the people doing crossfire/SLI. Some motherboards even provides X16 speed on both the primary and secondary but mostly cost a bit more also.

You can see the performace drop with x16/x4 setup Vs. x8/x8 setup in the chart below. Notice that the chart is for HD 6950, which by rule of thumb means that the faster your card is the more performance you will lose.


Of course you can debate that a x16/x4 is still faster than a single card setup but you won't get all of your money/performance out of your card and crossfiring is enough trouble as it is.
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July 24, 2013 6:32:16 AM

wanderer11 said:
Sorry if I made that unclear. What I meant is with the fps reported by FRAPS I don't know how many were runt frames so the number is most likely an overexaggeration of the actual fps.

As far as pcie bandwidth goes the rule of thumb is x8/x8 at least for CF/SLI. An x4 slot will reduce the overall performance. x4/x8/16 is basically how much data can be pushed through the pcie slot. More is better, of course.


i see...now it's much clearer to me. but in your case, the performance did improved to the point of "playing smoothly(much smoother than single card) with ultra setting" right?

I do want to try crossfire with my current mobo and gpu. But learning from your words...looks like it wont performed to its true potential since it's X4. However, if i do crossfire it, how much improvement you think (if possible to predict) in terms of fps or...smoothness (i know it's a subjective question)?.
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July 24, 2013 7:09:20 AM

Mahisse said:
Your motherboard's expansion slots specifications according to Gigabyte's website:

1 x PCI Express x16 slot, running at x16 (PCIEX16)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.
(The PCIEX16 slot conforms to PCI Express 3.0 standard.)
1 x PCI Express x16 slot, running at x4 (PCIEX4)
2 x PCI slots

So in english:
You have two PCIe x16 slots (Notice x16 slots is different from the speed x16. Here it means number of lanes. Very confusing;))
The primary slot is running with a bandwidth speed of x16 and the secondary is only running with a bandwith speed of x4. Actually I'm not into the technical terms of why this is but it has something to do with the motherboard not having automatic switches.

You can read more on it in this article:
http://www.tomshardware.com/reviews/pci-express-scaling...

Higher end motherboards have the ability to share the primary PCIe slot bandwidth with the second slot so they both become x8/x8 speed, which is minimum requirements for most of the people doing crossfire/SLI. Some motherboards even provides X16 speed on both the primary and secondary but mostly cost a bit more also.

You can see the performace drop with x16/x4 setup Vs. x8/x8 setup in the chart below. Notice that the chart is for HD 6950, which by rule of thumb means that the faster your card is the more performance you will lose.


Alright now i understand...thanks bro!

Looking at the chart, i will lose around 10fps (10%) of true potential if i do CF using my current mobo. Is it acceptable? depends on my taste. But looking at the chart you posted here, by CF hd6950 with 16X4 mobo spec ,the result for Alien vs Predator (medium, since not sure whether the chart you put is based on extreme or medium) is 114. for the single card, the result is 45 (regardless of whether it's 2gb or 1gb card). It seems like the performance is...at least double the single card. What do you think of it?

http://www.tomshardware.com/charts/2012-vga-gpgpu/compa...[5398]=on&prod[5397]=on
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July 24, 2013 7:17:42 AM

As I wrote in the bottom of my post (was edited so don't know if you saw it the first time). You will gain a performance boost over a single card BUT it is a matter of paying for something that you won't be able to exploit to the fullest. Also as you can see in the chart every game behave differently between x8/x8 vs x16/x4. Some are acceptable while some are not. Look at F1 for example.

Also your card is faster than the 6950 so your performance lose will be more vs. what your card COULD provide.
People do crossfire with a x16/x4 but if you ask me it's not worth the money and the motherboard should be upgraded first. But that is of course my personal opinion :) 
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July 24, 2013 7:26:49 AM

That chart is PCIE 2.0 since 6950s don't support 3.0. PCIE 3.0 is about a step faster than 2.0, for example PCIE 3.0x8 is similar to PCIE 2.0x16. So you will lose some performance, but not a lot. It's entirely up to you if that is acceptable or not.
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July 24, 2013 7:27:49 AM

That chart is PCIE 2.0 since 6950s don't support 3.0. PCIE 3.0 is about a step faster than 2.0, for example PCIE 3.0x8 is similar to PCIE 2.0x16. So you will lose some performance, but not a lot. It's entirely up to you if that is acceptable or not.
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July 24, 2013 7:41:56 AM

Mahisse said:
As I wrote in the bottom of my post (was edited so don't know if you saw it the first time). You will gain a performance boost over a single card BUT it is a matter of paying for something that you won't be able to exploit to the fullest. Also as you can see in the chart every game behave differently between x8/x8 vs x16/x4. Some are acceptable while some are not. Look at F1 for example.

Also your card is faster than the 6950 so your performance lose will be more vs. what your card COULD provide.
People do crossfire with a x16/x4 but if you ask me it's not worth the money and the motherboard should be upgraded first. But that is of course my personal opinion :) 


i understand it now. it's just a matter of 'loss of performance from it's true potential'. but for me i think it's still acceptable. if i want to change tio 7970 it will need me to top-up money around another 200-300$. So financially, i think CF is a more financially sense move rather than single 7970. furthermore, i have never done any CF before. i'm quite excited to experience it actually :ange: 

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July 24, 2013 7:44:34 AM

wanderer11 said:
That chart is PCIE 2.0 since 6950s don't support 3.0. PCIE 3.0 is about a step faster than 2.0, for example PCIE 3.0x8 is similar to PCIE 2.0x16. So you will lose some performance, but not a lot. It's entirely up to you if that is acceptable or not.


Wow thanks for highlighting that for me. I don't realize it at all. Now the more reason for me to go CF. :p 
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July 24, 2013 3:01:16 PM

Yep. If your board is PCIe 3.0x4 for the second slot (Which it should be for a haswell board), you'll see little to no performance loss, as its equal in bandwidth to PCIe 2.0 x8.
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July 24, 2013 4:01:09 PM

JJ1217 said:
Yep. If your board is PCIe 3.0x4 for the second slot (Which it should be for a haswell board), you'll see little to no performance loss, as its equal in bandwidth to PCIe 2.0 x8.


alright i'm all set. doing crossfire in the near future (sounds like years away, haha) and see how it's gonna perform.
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May 21, 2014 7:33:09 PM

wandere11
what is the motherboard you are using for crossfire gpu hd7870?
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May 21, 2014 7:37:00 PM

wander11
what motherboard u are using for crossfire dual fan hd7870?
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5 minutes ago

iam2thecrowe said:
no, crossfire is no good, it has been long believed, and now proven with new testing methods, that crossfire does not give the same performance increase that FRAPS records in benchmarking. Uneven spacing between frames, dropped frames, runt frames, all contribute to a perceivable frame rate at the monitor that is often no better than a single card, and sometimes the stuttering added by the secont card can make things worse than a single card. The stuttering is something that has been known for a long time, and new testing methods confirm this. AMD is expected to have a driver update to fix, or at least improve these problems. Wait until someone confirms this fix in the next driver release before you go crossfire. To add to this, what is your CPU and motherboard? if your cpu bottlenecked you may get no real performance increase anyway, and a 4x slot on your motherboard can increase stuttering due to even more uneven rendering speed between cards created by the slower slot, causing more stuttering.


Does this apply to Nvidias Multiple Gpu solution(SLI) too? If so will Gsync make it any better ?

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