Crossfire 7970 worse PERFORMANCE than single 7970

mick500

Honorable
Feb 23, 2012
174
0
10,680
I purchased a second MSI 7970 last week to go along with my original HIS 7970 as im using eyefinity. The single was working quite well with pretty much medium settings and no aa running about 45fps in most games like bf3, crysis 3 etc. Sometimes better sometimes slightly worse, but ALWAYS smooth. Anyway i though i would like to be able to turn aa back on and hopefully reach 60fps as well with a second card.

The result of adding the second 7970 has been less than pleasing, while frames per second have increased notably and i am indeed getting above 60 fps in nearly all games with aa turned back on the gameplay is extremely choppy and not smooth. Feels alot more like 20 to 25 fps on a single card, I'm wondering if anyone has any tweaks or solutions that may have worked for them, not necessarily in eyefinity but just with crossfire in general.

What i have tried so far..

I have the new AMD beta driver installed with the caps profiles.

I originally had the HIS 7970 in the top slot as the primary but switched them around and now have the MSI 7970 as primary for a very slight improvement. The HIS overclocks slightly better but i have them synchronized to the same speeds with afterburner to 1075 for core clock and 1550 for memory clock with +20 power limit.

I have tried rivatuner fps limiter with limited success. It seems to be the best bet so far. Some games still experience what i would describe as stutter rather than the choppy gameplay i described earlier which is a better result but still not ideal. Also i find myself having to limit my frames to what i could already achieve with a single card making crossfire pointless.

I have tried using D3D override and forcing triple buffering, again with limited success, not sure if v-sync should be enabled or disabled with triple buffer, or whether or not i should be using the fps limiter with triple buffer?

I have turned ULPS off in the registry.

I have tried at stock clocks and it just runs worse.

Any help with tweaks or anything at all would be great. Feel like i have just blown $400 bucks on a 2nd card that does little to nothing. Not to mention the eyefinity setup that is usable with a single card but not really at the level i would like meaning if i can't sort out crossfire it's a god chance i will be heading back to a single screen with a single gpu losing more money again in the process. Thanks.
 

mick500

Honorable
Feb 23, 2012
174
0
10,680
sorry guys, i have a asrock z77 extreme 4 motherboard, a corsair 850 watt power supply, 16 gig ram and a 3570k cpu overclocked to 4.4ghz. Can buying a different brand of gpu really make a difference? i read that the brand did not matter at all.
 

cbrunnem

Distinguished


Yeah I have seen multiple times on toms reviews that it has caused issues. It shouldnt most of the time but it is highly recommended to not miss match brands because it is really easy to buy the same brands in the first place compared to trouble shooting two different brands. I would return to match your original card.

I'm not really saying it is the problem but it's something that can be easily eliminated and that has caused issues in the past.
 

mick500

Honorable
Feb 23, 2012
174
0
10,680
It's not really a possibility. The original card is over a month old with no issues and the MSI card is from a shop that flat out refuses refunds unless the item is broken. I have them both running at the same clock speeds, shouldn't that negate any differences between the 2??
 

mick500

Honorable
Feb 23, 2012
174
0
10,680



Yeah i have, it doesn't overclock quite as well, can only get 1075 and 1550 where the HIS can get upto 1125 and 1575 and be totally stable and could probz go even further, but yeah the msi works fine on its own.
 

mick500

Honorable
Feb 23, 2012
174
0
10,680



So are you still needing to use a frame rate limiter with the same manufactured cards? Would flashing the bios of the cards to the same bios resolve that issue or likely still have differences?
 

jthill909

Honorable
Nov 6, 2012
198
0
10,710
Hopefully this'll help you out.

I have a setup near the same as yours. I am running a 3570k @ 4.4 on an ASRock Extreme 4. I am currently running a crossfire setup with two 6870's. They are both reference models.

When I first purchased the second card, I found that the microstutter was unbearable for most games (BF3, etc.). So, I went away from the two card setup for a while. Recently, though, I reinstalled the second card and found a program called RadeonPro which helps tremendously with a crossfire setup.

Basically, what you can do with RadeonPro is create a crossfire profile for each game you play and what you are going to end up doing is forcing Triple Buffering and a Dynamic FPS. I have my Dynamic FPS set at 59 fps so that I won't get any tearing because of my 60 Hz monitor.

What this is doing is forcing a custom VSync profile for every game (you will have to create a profile for each individual game, but you can create a global profile for all games, but you'll want separate profiles) which will eliminate 99% of all microstutter. I haven't experience any microstutter since doing this and finally enjoy having two cards. Tom's actually has an article that briefly talks about RadeonPro.

Try it out and see if it helps you.
 

cdrkeen

Distinguished
Feb 9, 2009
172
0
18,710
From what I understand, there should be a switch to change from a locked bios to an unlocked one. I believe it's switch 1 you want it set to. If the bios doesn't work, all you have to do is set it back to the locked bios(switch 2). So there shouldn't be any risk, someone correct me if this is wrong but I'm pretty sure.
 
Hopefully, you're not experiencing what PC Perspective discovered in their recent series of reports. Yes, they are showing the 7970 Crossfire setup to be slower than a single card in Crysis 3:

Crysis3_5760x1080_PER.png

http://www.pcper.com/reviews/Graphics-Cards/Frame-Rating-Dissected-Full-Details-Capture-based-Graphics-Performance-Test-5
 
The issue is obviously that Crossfire does not have frame metering built in. If you create a bottleneck, frame spacing occurs because it forces time between each card starting a new frame. Those tests show without v-sync or a FPS limiter, which has been shown to help. Unfortunately with Eyefinity, at least 5760x1080 does not support v-sync, so you'll have to fix it with some sort of FPS limiter. You'll also have to create a limiter for each game you play, because you probably won't want it lower than your average FPS, or have it so high that it doesn't do anything.
 

cdrkeen

Distinguished
Feb 9, 2009
172
0
18,710


Well if you have a card with a dual bios which I believe all 7970's have, you can't brick a card. There will be a locked default bios you can change back to with a flip of the switch if something goes wrong. Also if you're running crossfire which he is. He could still boot up his system and flash the bad bios back to the original one. Obviously using gpuz to back up bios beforehand. I actually did it myself recently. I flashed back the bios to the original because I had to rma a card. So it shouldn't ever void the warranty if the proper steps are taken.
 

cdrkeen

Distinguished
Feb 9, 2009
172
0
18,710


So then what other risks are there. If he has a dual bios then there are no risks.
 


Back when the 6950's were first brought out, a lot of people flashed 6970 bios on their cards. Not long after, many people had video card damage to their VRAM. Using a bios not designed for the card can use timings not meant for that card that can cause damage.
 

cdrkeen

Distinguished
Feb 9, 2009
172
0
18,710


I see, good to know. Didn't know there was a difference in timings for vram on a gpu. It shouldn't be much different for gddr5 unless they are using inferior quality vram.

 

cdrkeen

Distinguished
Feb 9, 2009
172
0
18,710

Flashing a bios isn't as risky as you're saying. Not sure why you keep saying the same thing over and over after I already explained this. If he has a dual bios then you won't void your warranty because you can flash it back to the original. Now if he does accidentally put the wrong one in then it would damage the card possibly voiding it. But they most likely would see it as a faulty card. You cannot test the card when it won't boot up.

 
As simple as it may seem, some situations don't always turn up rosy, or require a lot of effort. Look through these instructions I created once: www.tomshardware.com/forum/316974-33-radeon-6950-shader-unlock-instructions#t2368661

If you look through the post, there are a number of people who bricked their cards and spent a lot of time and effort trying to unbrick them. It seems every case was different and had different requirements to unbrick them. Granted, none of them had dual bios switches, but flashing isn't all that risk free either.
 

mick500

Honorable
Feb 23, 2012
174
0
10,680
Thanks for the discussion about the bios flashing, i gotta say i tend to agree with bigmack70, considering it's $800 worth of gpu i would only do it as a last ditch effort if i was pretty confident that was the issue. I really don't think different manufacturers should matter, they are both running at the same clock speeds and some games like black ops 2 run fine in crossfire. but the majority of them are broken. So yeah, still at a loss.
 

mick500

Honorable
Feb 23, 2012
174
0
10,680


Not sure exactly what sort of scores i should be getting , but i got 40,800 in 3D mark vantage and i think that sounds about right? GPUZ and Afterburner both read the cards fine, Well gpuz and afterburner seem to read everything okay, but under the sensors tab the second card does have alot less information? Is that normal? The first card lists about 15 things while the 2nd car only lists 6. It has the main info tho, like core clock, memory clock etc. Apart from that the only other difference listed is the bios version and sub vendor.


 

It sounds like the only issue is the standard CrossfireX limitations on metering. V-sync and FPS limiters are your friend, unfortunately v-sync doesn't work in Eyefinity, so look at FPS limiting.

 

cdrkeen

Distinguished
Feb 9, 2009
172
0
18,710

No one is picking fights here except for you. You keep spreading miss information in these threads. With a dual bios there is a very small risk of bricking your card. If you dont know what you're doing and are dumb you will void your warranty. There is nothing else to say about this. Stop miss informing people just to feel good about yourself.

 

mick500

Honorable
Feb 23, 2012
174
0
10,680



well do you know of a decent tutorial for flashing a 7970 if i get desperate enough to try it?