7870 + 280x Xfire Issues

I got me a new 280X over the weekend and I still have my 7870XT for a few weeks and thought Id try Xfire.

But Im getting some performance issues.

In 3DMark's fire strike test with my 280X i get around 7600. I can break 8K with an OC.

But with the 280X and 7870XT in Xfire I am getting a score of 6371.

I did notice that the GPU load for the 280X was around 40% while the 7870XT was at 99%

Thoughts?

 

Don't know how true this is, but:

Quote:
Indeed you cannot CF a 7870 with a R9-280X. because they use 2 diffrent gpu´s.


https://teksyndicate.com/forum/gpu/can-i-crossfire-hd-7870-r9-280x/159285

 

Yep, you can crossfire a 280x with a 7970, I think also with 7950 (because 7950+7970 works fine in cfx) and a 280 (7950 in disguise). 7870 is a different chip.

 

Im not using a 7870.

Its a 7870 XT, it uses A Tahiti GPU the same as the 7950/7970/280/X And not a pitcarin.

Xfire Is enabled.

http://gyazo.com/db8fb0cbfc785e5dd0a83d9b70b5a86e

http://gyazo.com/8d8d4947899b4a2b7ea3cd9c964c202e

 

Do the PCIE speeds and lanes jump up to full speeds when you hit the ? render test on GPU-z ?

 

Ah ha,

Ok so, the 280X is running at PCIE 3.0 @ x8 while the 7870XT is stuck at 1.1

Even setting GEN 3 in the bios for both PCIE lanes is not working.

 

Id have a shot of removing the drivers in safemode with DDU and reinstalling them
http://www.wagnardmobile.com/DDU/

Ive sorted out stuck PCIE lane speeds that way before

If that fails, try clearing CMOS and setting it up again

Also try changing slots the cards are in, reverse them etc

 

No luck switching the cards. but the same slot is stuck at 1.1

At first I had the 7870 in the 2nd slot, stuck at 1.1 now the 280x is in the 2nd slot and stuck at 1.1.

I am just re-installing drivers now and also re-flashing my bios.

EDIT:

Seems to have done the trick.. will run Fire Strike

 

Are you checking the "Full screen for CFX" box ?

You should be getting 2 x 8x according to your boards specs

- 2 x PCI Express 3.0 x16 slots (PCIE2/PCIE3: single at x16 (PCIE2) / x8 (PCIE3) or dual at x8/x8 mode)

Are you deffinetly using the correct PCIe lanes too? Because it also states 2 x PCI Express 2.0 x1 slots

EDIT - Just seen your edit lol

 

Any joy ?

 

Not sure, just running some tests.

GPUZ is being a pain, It freezes and lags if I chose my 7870 from the drop down list.

 

Does it still freeze when CFX is disabled ?

 

Ah, I see , its doing it when the card is in ULPS but fine when the card is on and doing something.

Here is my score.

http://www.3dmark.com/3dm/4119890?

Not as good as I thought it would be.

 

Better than 83% of all results


Not bad though, I got 5108 with my old 7870 and , so CFX scaling is about normal, you don't get 100% scaling, more like an extra 70% boost




6005 Graphics score vs yours @ 10760 - seem about right

 

As long as its performing ok.

I may get a 2nd 280x but its a hard choice since the gtx980 is around £440 and 2 280x is gonna be £380

 

100% Id go with the 980

As fun as the extra benchmark scores are with CFX, my experience was anything but fun when it came to gaming, many games performed worse with CFX than a single card, to the point where I had 2 x 6850s and one of them sat on my desk for last 6 months I owned it because of CFX issues

 

What do I have the option of pairing my 290x with?

 

Quick search brought up this:

I just go with the rule that if the cards have the same base core they will work together.

R9 295X2 R9 290X and R9 290 are all compatible

HD7990 HD7970 HD7950 HD7870XT R9 280X R9 280 are all compatible but a bit of headache when you mix HD with R9

HD7870 HD7850 R9 270X R9 270 R7 265 are all compatible

The lower cards follow similar rules but you really shouldn't be CFing those os I won't go over them.

Also when you run to different cards in CrossFire it's called CrossFireX.

Hybrid CrossFire is when you CrossFire an APU with a GPU and as far as I know it's pretty broken.

 

ignore me I cant read

 

That's a pretty low score, my 7950 cfx easily beat 16k in fire strike.