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Crossfire 7870's


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#1 madd-hatter

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Posted 05 December 2013 - 02:08

I have

http://www.newegg.co...N82E16814102981

 

I'm looking at a deal for one of these

http://www.newegg.co...N82E16814202024

 

Would I lose performance with slightly different cards or would I be best to match my card as much as possible?

It's Tahiti vs Pitcairn architecture. I don't know what that means, perhaps you do?




#2 Scorpian8867

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Posted 05 December 2013 - 02:49

As far as I can tell, the 7870 XT cannot crossfire with any 7800 series cards. You'll need a 7850, 7870 (GHz), or R9-270(x) to double-up with what you have right now.



#3 Jason S.

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Posted 05 December 2013 - 14:22

yeah i think you're sol.

 

however, correct me if im wrong, but why not just get another one, like this?

http://www.newegg.co...N82E16814202025



#4 OP madd-hatter

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Posted 06 December 2013 - 04:49

yeah i think you're sol.

 

however, correct me if im wrong, but why not just get another one, like this?

http://www.newegg.co...N82E16814202025

Is this fully compatible?



#5 +snaphat (Myles Landwehr)

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Posted 06 December 2013 - 05:11

You may want to look up micro-stuttering. ATI card tend to have it still in crossfire AFAIK:

 

http://www.tomshardw...sfire,2995.html



#6 Circaflex

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Posted 06 December 2013 - 05:34

You may want to look up micro-stuttering. ATI card tend to have it still in crossfire AFAIK:

 

http://www.tomshardw...sfire,2995.html

Now I am not disagreeing with you as MS is in both nVidia and ATI/AMD but you really should use a more recent article than that "By Igor WallossekGreg Ryder

AUGUST 21, 2011"

#7 Scorpian8867

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Posted 06 December 2013 - 06:09

Microstuttering in crossfire setups is nowhere near what it was back then. I've been using dual 7970's for over half a year now, and it's never been a problem for me. Especially not after the frame pacing drivers that AMD released not too long ago.

 

Also, yes, that card will work with yours. Any 78xx card will work with any other 78xx card. The only exception is the 7870 XT, which uses a Tahiti core. The R9-270 & R9-270x will both work as well since they have the same core.



#8 +snaphat (Myles Landwehr)

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Posted 06 December 2013 - 06:09

 

Now I am not disagreeing with you as MS is in both nVidia and ATI/AMD but you really should use a more recent article than that "By Igor WallossekGreg Ryder

AUGUST 21, 2011"

 

 

Honestly, you need look up what you are saying instead of concluding that what I linked wasn't relevant because of the date. Perhaps, I was simply providing an article that demonstrated the issue for the OP in case he didn't know about it. Moreover, perhaps, I specifically mentioned ATI cards and told the OP to look up the issue for a reason:

 

http://www.tomshardw...iver,23214.html

http://en.wikipedia....icro_stuttering

 

I didn't want to get into it before because there really shouldn't be an argument about it, but SLI hasn't had an issue for years. By far the largest offender in micro-stuttering has been AMD. Earlier this year, nVidia even provided a tool called FCAT as a marketing gimmick just to show how ATI cards still had issues with micro-stuttering. I could provide benchmark articles, but I am fairly sure you are capable of searching yourself for benchmarks that show the results with CrossFire and SLI. Unless something has changed drastically in the last 6 months: AMD still has issues. And, I really doubt anything has drastically changed since architecture issues don't particularly fix themselves with driver updates. You can alleviate some of the issues, but software solutions for hardware problems generally don't end so well.

 

Not, that I would ever buy NV cards since they tend to be much less cost effective in terms of price/performance ratios.



#9 +snaphat (Myles Landwehr)

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Posted 06 December 2013 - 06:15

Here's a link to benchmarks and things with the frame-pacing drivers:

http://www.tomshardw...re,3595-10.html

 

EDIT: actually these results are much better than I anticipated. Though, not perfect.



#10 Scorpian8867

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Posted 06 December 2013 - 06:25

August's frame pacing drivers are the first in a stream of updates designed to implement a proper frame metering solution, which AMD/ATi has historically lacked (as pointed out in that first aritcle you linked). The initial release only supports Dx11 titles in the standard range of resolutions (everything below 1440p, if memory servers) on single-monitor setups. The next revision is expected to include improved performance, support for Dx9 and 10, higher resolutions, and eyefinity. I believe AMD claimed that it would be released in late fall, but it looks like that got delayed. Not really surprising. It took them several months to get the first release stable enough for a beta release. I heard that the early preview version sent out to a few reviewers was unbelievably buggy. The proper beta release was pretty stable though.



#11 +snaphat (Myles Landwehr)

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Posted 06 December 2013 - 06:31

August's frame pacing drivers are the first in a stream of updates designed to implement a proper frame metering solution, which AMD/ATi has historically lacked (as pointed out in that first aritcle you linked). The initial release only supports Dx11 titles in the standard range of resolutions (everything below 1440p, if memory servers) on single-monitor setups. The next revision is expected to include improved performance, support for Dx9 and 10, higher resolutions, and eyefinity. I believe AMD claimed that it would be released in late fall, but it looks like that got delayed. Not really surprising. It took them several months to get the first release stable enough for a beta release. I heard that the early preview version sent out to a few reviewers was unbelievably buggy. The proper beta release was pretty stable though.

 

I still question whether they will be able to provide a silver bullet via software-only in the end. I think it is something that is going to require a hardware redesign to completely eliminate. Perhaps, that is why the stalls have come into play?

 

As for the practicality of the issue, I don't have a dual-card setup so I can't comment on how perceptible it is to the average person at the end of the day though.



#12 Circaflex

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Posted 06 December 2013 - 06:32

Here's a link to benchmarks and things with the frame-pacing drivers:

http://www.tomshardw...re,3595-10.html

 

EDIT: actually these results are much better than I anticipated. Though, not perfect.

so my point exactly, its not as bad as your 2011 article puts it, were in 2013 theres a reason i said your article was outdated



#13 Scorpian8867

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Posted 06 December 2013 - 06:38

I still question whether they will be able to provide a silver bullet via software-only in the end. I think it is something that is going to require a hardware redesign to completely eliminate. Perhaps, that is why the stalls have come into play?

 

As for the practicality of the issue, I don't have a dual-card setup so I can't comment on how perceptible it is to the average person at the end of the day though.

It can be done entirely on software. Not perfectly, of course, but it's not like a hardware solution would fix it either. You'd probably need two GPUs exactly right next to each other on the same PCB with access to the same memory in order to totally eliminate any latency that could lead to that. Not even the dual-GPU card solutions from either team offer that. The only thing that can be done is to hack away at the severity of the issue until it's so hard to notice that nobody complains anymore. AMD's software-only approach seems to be working well so far. It's a bright future if they keep expanding on it.



#14 +snaphat (Myles Landwehr)

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Posted 06 December 2013 - 06:40

so my point exactly, its not as bad as your 2011 article puts it, were in 2013 theres a reason i said your article was outdated

 

I'm honestly not sure what to make of that given that you downplayed the issue to sound like nothing and also implied NV cards have the same problem. :huh:



#15 +snaphat (Myles Landwehr)

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Posted 06 December 2013 - 06:46

It can be done entirely on software. Not perfectly, of course, but it's not like a hardware solution would fix it either. You'd probably need two GPUs exactly right next to each other on the same PCB with access to the same memory in order to totally eliminate any latency that could lead to that. Not even the dual-GPU card solutions from either team offer that. The only thing that can be done is to hack away at the severity of the issue until it's so hard to notice that nobody complains anymore. AMD's software-only approach seems to be working well so far. It's a bright future if they keep expanding on it.

 

Of course, you can't eliminate it completely*, but hardware solutions do go a long way. Does NV even have frame pacing in their drivers? I'm not aware of it if they do (I can't say I've particularly looked very hard though). I think the difference in architecture alleviates the issue much on its own.

 

* That is a little too strong. Some clever hardware engineers may make the issue a thing of the past at some point. You never know. Operate on the same clock tick somehow?

 

EDIT: found this: http://developer.dow...es_2011_Feb.pdf