7850 Crossfire has failed me this round. Sent 2nd card back. Sticking with one card.

[bigsnyder]

Wait a minute everyone - I think we have to correct this - a 4850 and a 7850 cannot be crossfired, regardless of memory size.

Never say never

 

[SlowSpyder]

Never say never

Even if you could do this, it would probably be slower than a 7850 by itself. I imagine the 7850 would spend a lot of time waiting for the frame to be rendered by the 4850. But, you can't do that anyway, so it's all moot.

 

[iCyborg]

Wait a minute everyone - I think we have to correct this - a 4850 and a 7850 cannot be crossfired, regardless of memory size.

Chuck Norris can Tri-Fire 4850, 7850 and GTX 675M

 

[kalrith]

Even if you could do this, it would probably be slower than a 7850 by itself. I imagine the 7850 would spend a lot of time waiting for the frame to be rendered by the 4850. But, you can't do that anyway, so it's all moot.

The 7850+4850 CF discussion started because the OP wants to test his motherboard's CF capability. If it works great with 4850 CF but has lots of problems with 7850 CF, then it's like a problem with the 7850s. If it doesn't work well with 4850 CF, then the problem might be his mobo.

So, he obviously doesn't want 4850 CF performance; it's just a troubleshooting test.

 

[jacktesterson]

EDITED FOR BENCHMARKS:


1200 Core, 1375 Memory

3DMARK11 Top Score Overall - P11787
http://3dmark.com/3dm11/3402572;jsessionid=rys4f3hqon2u1t31fq6zdwbp7

3DMARK11 Top Graphics Score- 13677

Update May 16th





Woke up this morning to more stability issues after leaving the PC on all night, running stock..

I have RMA'd the 2nd card and am sending it back.

Sticking with the one original card, this has really turned me off from Crossfire... and I'm happy with the performance of one card overclocked. (Plus my original O/C's much better)

I was about to pull the trigger on a single 670, but after much thought, I've actually been very pleased with the performance of my original 7850 and just decided to sit on that.

Sorry for the back and fourth, but its packed up and being dropped off today.

 

[jacktesterson]

Well I managed to get a 2nd 4850 from somebody just to test my motherboard last night, and everything went without a hitch using 12.4's. Guess my motherboard doesn't seem to be the issue.

No issues at all stock.

Guess it is bad drivers, or my Asus cards just don't like the drivers available now.

Crossfire is a complete mess right now for 7850's.... and even worse when you try to bring in overclocking in Crossfire mode.

Overclocks that are completely stable solo are not when crossfired, and I still cannot figure out why my cards are throttling when in Crossfire, even when running 100% max fan speed with low temps.

Packed up the 2nd card and sent it back. Really turned off by crossfire with this experience.

 

[blackened23]

You can't get the same overclocks period with dual gpu, thats just a fact of life. Your 2 chips are different and when you are trying different voltages and clocks on both in crossfire or sli you are begging for problems. Fact of the matter is every chip has different quality and 1 chip that may do "X" speed, but when you try to crossfire it with another card and get Card 2 to also do "X" speed when it can't, boom, problems. I've dealt with this issue on a number of GPU's, happened with lightning sli's. Don't have grandiose and unrealistic expectations of overclocking with crossfire or sli. It won't be as good as single card if you can do it at all. You shouldn't expect much more than stock speeds if you're crossfiring, period.

Anyway, why not just opt for a 670 rather than 2 7850s? Seems to make more sense. You should RMA the other card as well IMO

 

[railven]

Wow....so overclocking is hardder in crossfire? Well sorry to be cynical but no joke are you kidding? You can't get the same overclocks period with dual gpu, thats just a fact of life. Your 2 chips are different and when you are trying different voltages and clocks on both in crossfire or sli you are begging for problems. Fact of the matter is every chip has different quality and 1 chip that may do "X" speed, but when you try to crossfire it with another card and get Card 2 to also do "X" speed when it can't, boom, problems. I've dealt with this issue on a number of GPU's, happened with lightning sli's. Don't have grandiose and unrealistic expectations of overclocking with crossfire or sli. It won't be as good as single card if you can do it at all. You shouldn't expect much more than stock speeds if you're crossfiring, period.

Anyway, why not just opt for a 670 rather than 2 7850s? Seems to make more sense.

Read more of the thread, I believe he tried all combinations possible:
Each card at it's best OC
Both cards at the lowest capable OC
Both cards stock

AMD botched something bad. If I were him I'd have given up a long time ago. Kudos for even trying to fix this mess and going the extra mile to remove probable issues such as the motherboard.

Glad I use one GPU in my rig. Woof.

 

[blackened23]

Ah okay I misunderstood. My bad. The impression I got was that it was due to not being able to OC in crossfire. Nevermind then.

 

[railven]

Ah okay I misunderstood. The impression I got was that it was due to not being able to OC in crossfire. Nevermind then.

From what I've read, my interpretation was that the lack of OC freedom via CFX was the straw that broke the camel's back. He got it to work after trying multiple driver revisions, and in the end he wasn't happy with the work and results. So why bother it anymore at that point?

As an AMD supporter it is a little defeating to see the number of "help my HD 78xx series has x-problem" that popped up after they launched.

Something seems to be screwy with the 78xx series. Being AMD's best price/perf card line up - they should really fix all known issues with them cards else they give up just more ground to NV.

 

[blackened23]

From what I've read, my interpretation was that the lack of OC freedom via CFX was the straw that broke the camel's back. He got it to work after trying multiple driver revisions, and in the end he wasn't happy with the work and results. So why bother it anymore at that point?

As an AMD supporter it is a little defeating to see the number of "help my HD 78xx series has x-problem" that popped up after they launched.

Something seems to be screwy with the 78xx series. Being AMD's best price/perf card line up - they should really fix all known issues with them cards else they give up just more ground to NV.

So now i'm completely confused. So it was because of OC's? If it is, thats ridiculous, if its not that, apologies for my misunderstanding. Nevermind.

 

[Don Karnage]

I wish Xfire would work. Would love to see what 7850's could do at 1300

 

[railven]

So now i'm completely confused. So it was because of OC's? If it is, thats ridiculous, if its not that, apologies for my misunderstanding. Nevermind.

You can just read the thread. OC's were a factor, but before that he had to jump through hurdles to even get CFX to work properly. (And yes, I'm aware countless others and reviewers don't have these issues, but in the end their experience isn't the OP's experience.)

Like I said, the OC's seemed to just be the straw, the stuff before it was the real reason.

 

[jacktesterson]

From what I've read, my interpretation was that the lack of OC freedom via CFX was the straw that broke the camel's back. He got it to work after trying multiple driver revisions, and in the end he wasn't happy with the work and results. So why bother it anymore at that point?

As an AMD supporter it is a little defeating to see the number of "help my HD 78xx series has x-problem" that popped up after they launched.

Something seems to be screwy with the 78xx series. Being AMD's best price/perf card line up - they should really fix all known issues with them cards else they give up just more ground to NV.

Its my fault.

I've been all over the place in this thread, simply because I've had so many random issues and problems I can't remember them all.

You are correct though, I got the cards working in crossfire at least half decent using older drivers, but I was unaware of how much crossfire takes away O/C capability.

I tried running them at indentical specs. I also tried running same clocks but with optimized voltages for each. (When running solo). I had a hard time to reach 1150 stable.

Anyways, its not the end of the world. I'm just done toying with it. I'll just enjoy a O/C'd stable single 7850 for now, and upgrade down the road when needed.

 

[jacktesterson]

So now i'm completely confused. So it was because of OC's? If it is, thats ridiculous, if its not that, apologies for my misunderstanding. Nevermind.

I'm not being ridiculous. I've had such a bad experience overall with these cards I honestly almost sent them both packing and was going to go 670. Just getting Crossfire TO WORK OUT OF BOX was a challenge.

O/C's are never guaranteed, I know. Thanks for the input though. I was in fact surprised about the O/C'ing issues when in Crossfire. It's just a small part of the pie.

 

[jacktesterson]

I wish Xfire would work. Would love to see what 7850's could do at 1300

If you can get them running decent, I'd be very surprised to see anyone getting them to 1200, besides 1300.

I know O/C's are not guarenteed, but I was unaware of Xfire impacting overclocking. Rookie mistake. I'm still within the return period, and I think my experience has warranted giving up for what my goals were.

As stated earlier, others have not experienced these issues, although I've yet to see anyone claim to be running 12.3, 12.4 or 12.5 beta's on 7850 Xfires.

 

[Don Karnage]

Adam did yu ever consider flashing them both to the asus top bios?

When i ran my 5770's in Tri i had them all flashed to the Asus top bios. Ran flawlessly overclocked that way

 

[jacktesterson]

Adam did yu ever consider flashing them both to the asus top bios?

When i ran my 5770's in Tri i had them all flashed to the Asus top bios. Ran flawlessly overclocked that way

Already sent one back this morning.

My original card is going to be pushed tonight. If I feel I can get more, I may try the TOP bios, although I doubt it would do anything other than increase stock clocks.

They appear to be identical cards other than the OC.

 

[Don Karnage]

Already sent one back this morning.

My original card is going to be pushed tonight. If I feel I can get more, I may try the TOP bios, although I doubt it would do anything other than increase stock clocks.

They appear to be identical cards other than the OC.

TOP bios is most beneficial to people who dont own an Asus card

 

[SickBeast]

TOP bios is most beneficial to people who dont own an Asus card

Is there any difference between the TOP and the non-TOP bios aside from clockspeeds? I have the non-TOP bios and I can still use 1.3v.