Considering crossfire - yay or nay?

panyan · 26 Dec 2011 at 12:37

i went from single to crossfire 5850's two days ago, it was rather simple and on first boot with the new card i booted up bf3 and it worked straight away and im getting similar fps to my gtx 580

the only thing i didnt realise was that it doesnt combine the vram of the cards, my 5850's each have 1gb of vram, but that doesnt mean in crossfire it can use 2gb, it can only use the vram of the primary card (1gb)

btw, you may experience a little microstutter, i did too, but i think it is so insignificant that i couldnt really see it anyway - i have backed it off down from ultra to high and i dont experience it at all now (or at least i cant even detect it) and it plays lovely and buttery smoothly

AMG · 26 Dec 2011 at 13:51

I used to run a Xfire setup, without major issues

isnt X58 16/16 ?

[WU-TANG]GZA · 26 Dec 2011 at 14:28

tommybhoy said:
I presume you can watch youtube videos on your phone:

This was a small video showing BF3 fps taken on release with the Catalyst 11.10 preview2 + Cap3 .

Performance has had a good boost since then too, using newest drivers here and performance is rock solid.

Not swapping my CrossFire for the 7970, as(with a little patience sometimes) 6950>70 CrossFire will beat the 7970 the majority of the time @1080p.

Thanks for this.

OK so whack the MSI on the top and 12.1 drivers currently best.

Think I'll go toss a coin....

LtMatt · 26 Dec 2011 at 14:36

[WU-TANG]GZA;20879308 said:
Have you ever tried the xfire without AA just so I can compare. Benchmarks are one thing but I'd like a user stat.

I've got it in my basket now, added the voucher code, chosen delivery date.

Just not sure if I'm being a bit silly and 'wasting' £250. Hmmm....

Next time i load up the game ill tell you. I would imagine 60fps solid with vsync.

inSilica · 26 Dec 2011 at 15:32

I started off considering 2 x 6950's in crossfire as they posed best value for money.

Because I cannot be bothered to wait for the 7990 I will be treating myself to a 7970 by the end of January. When the waterblock is released I will probably grab a second 7970 later on.

If the 7950 will pose a better deal I may be swayed.

The reasoning behind my initial comment was as *Alexrose1uk* said ... the crossfire 6970 will perform better in the short run, though it will "plateau quicker". In the immediate short run I prefer fewer framerates now ... pickup a second 7970 later ... and have a more power efficient and longer lasting setup.

arc@css · 26 Dec 2011 at 15:53

inSilica said:
I started off considering 2 x 6950's in crossfire as they posed best value for money.

Because I cannot be bothered to wait for the 7990 I will be treating myself to a 7970 by the end of January. When the waterblock is released I will probably grab a second 7970 later on.

If the 7950 will pose a better deal I may be swayed.

The reasoning behind my initial comment was as *Alexrose1uk* said ... the crossfire 6970 will perform better in the short run, though it will "plateau quicker". In the immediate short run I prefer fewer framerates now ... pickup a second 7970 later ... and have a more power efficient and longer lasting setup.

I hope you won't be pairing the 7970 cards with the cpu in your sig?

inSilica · 26 Dec 2011 at 16:22

arc@css said:
I hope you won't be pairing the 7970 cards with the cpu in your sig?

LoL ... no. Planning on building SB-E once the C2 stepping is release on Jan 20th. Been running this setup for almost 6 years! sheesh

[WU-TANG]GZA · 26 Dec 2011 at 17:27

inSilica said:
I started off considering 2 x 6950's in crossfire as they posed best value for money.

Because I cannot be bothered to wait for the 7990 I will be treating myself to a 7970 by the end of January. When the waterblock is released I will probably grab a second 7970 later on.

If the 7950 will pose a better deal I may be swayed.

The reasoning behind my initial comment was as *Alexrose1uk* said ... the crossfire 6970 will perform better in the short run, though it will "plateau quicker". In the immediate short run I prefer fewer framerates now ... pickup a second 7970 later ... and have a more power efficient and longer lasting setup.

Yeah but surely that will always be the case and I would therefore follow that reasoning again and just get a 8970 instead of xfire 7970s and never have xfire raw power goodness.

Thanks all for thoughts and advice.

ALXAndy · 26 Dec 2011 at 17:29

ne'er a truer word spoken.

inSilica · 26 Dec 2011 at 17:30

[WU-TANG]GZA;20883709 said:
Yeah but surely that will always be the case and I would therefore follow that reasoning again and just get a 8970 instead of xfire 7970s and never have xfire raw power goodness.

Thanks all for thoughts and advice.

Sure, if it wasn't being released in a fortnight.
I follow your answer i.e. I don't intend to wait for the 7990 which will be released in March!

I'm sure you will have a great time either way you go ...

Good luck

V F · 26 Dec 2011 at 19:58

panyan said:
i went from single to crossfire 5850's two days ago, it was rather simple and on first boot with the new card i booted up bf3 and it worked straight away and im getting similar fps to my gtx 580

Nice.

the only thing i didnt realise was that it doesnt combine the vram of the cards, my 5850's each have 1gb of vram, but that doesnt mean in crossfire it can use 2gb, it can only use the vram of the primary card (1gb)

btw, you may experience a little microstutter, i did too, but i think it is so insignificant that i couldnt really see it anyway - i have backed it off down from ultra to high and i dont experience it at all now (or at least i cant even detect it) and it plays lovely and buttery smoothly

Why hasn't it been designed by now to use the second cards VRAM... two generations later and they haven't changed it.

ALXAndy · 26 Dec 2011 at 20:03

V F said:
Nice.

Why hasn't it been designed by now to use the second cards VRAM... two generations later and they haven't changed it.

They can't change it man, that's how it works.

I have Quad SLI, it gets a whopping 798mb vram to play with, and over 2gb sits dormant. It's really annoying :mad:

V F · 26 Dec 2011 at 20:36

ALXAndy said:
They can't change it man, that's how it works.

...and why not?

jonnylaris · 26 Dec 2011 at 20:39

If you enjoy microstutter then dive right in

ALXAndy · 26 Dec 2011 at 21:03

V F said:
...and why not?

Because they would literally have to invent something new and that's too much work.

Do you know where SLI came from?

DustyMiller · 26 Dec 2011 at 22:15

My crossfire 6870's are excellent, never had a single issues with them.

Alexrose1uk · 26 Dec 2011 at 22:36

V F said:
...and why not?

Because both cards work from the same video data, and the same textures, if they set it so only one card had to host a copy of the data, if the other card needed it you'd constantly be having to trade data and it'd increase latency with memory requests, and additional CPU time, neither of which would benefit seamless dual card rendering.

This one one of the things people had been hoping sidelink would help with back in the 4 series days, but it wasn't enabled and used for a reason.

DrBombcrater · 26 Dec 2011 at 22:55

V F said:
Why hasn't it been designed by now to use the second cards VRAM... two generations later and they haven't changed it.

Combining the memory of two graphics cards is one of those things that sounds simple, but when you actually try and find a way to do it turns out to be a nightmare.

In order to share memory without completely killing performance each GPU needs to be able to access the other card's memory at similar speeds to its own. The problem is speed: video memory on modern graphics cards is very, very fast - around 130GB/sec on a Radeon 6870, rising to about twice that on the new 7970.

The signal integrity and timing problems involved in moving data at that kind of speed are non-trivial, to put it mildly. Doing it on a graphics card's PCB with the GPU and memory chips separated by a couple of centimetres is hard. On a dual-GPU card, where the distance would go up to 3-4 inches, would be very problematic and expensive. Two seperate cards, there's no chance whatsoever.

So, don't hold your breath for shared memory. Physics dictates that it's not happening without some major breakthrough in technology that's not even on the distant horizon right now.

Sayso · 27 Dec 2011 at 01:44

For me personally being old...i cant tell the difference between high or ultra in BF3 (it all just looks like magic when the first game you played was on an Atari in the early 80s) ive thought about using a dual card set up but i can play happily at 30fps (i know some people find this unacceptable but see above) sorry im drunk and cant remember the point i was going to make...happy christmas

DazQ87 · 27 Dec 2011 at 01:59

Not had any real issues with crossfire, I have been running my two 5850s for a good 18 months now (got my first one on release week and got my 2nd 6 months later).

keep on top of all the drivers and profiles and you will be ok. However, given the choice i would deffinatly take a single card over two, even if the performance wont be as good. Mainly from a noise perspective (that and sometimes you do get niggles with new games).

I myself will be getting a new single card before the end of january, either an AMD 7970/50 or if they are just too expensive I am very tempted to jump back to the green team for a 580. (the upgrade/new tech itch is very very irritating, especially when you havent bought a new GPU for 18 months

)