Crossfire 5850, first impressions from a multi-GPU noob

d_brennen · 28 Sep 2011 at 23:20

First time I have used CF myself, after years of reading about the pitfalls of CF installs I've put it off. Having owned a 5850 since launch it was only just becoming a little lacking for me. Still an awesome performer considering it's from late 2009! Decided to bite the bullet and get another for CF as the 69xx cards don't really look like good value from where I'm sitting

My setup

Screen: Dell S2409W 1920x1080
PSU: 700w OCZ ModXstream
CPU: Phenom II X6 1055t @ 3.5GHz (does 4GHz but I like a quiet idle and can't get C&Q working at that clock)
RAM: 4GB DDR3 1600
GPUs: 2x reference 5850s (one ATI branded, one Sapphire, physically identical bar sticker, 775MH/1100MHz for now)
Motherboard: Asus M4A89GTD Pro
Case: Fractal Design XL, 3 x 140mm fans/1 x 120mm fan / 1 x 200m roof fan, all low speed

With much trepidation I plugged in the second 5850, power connectors and CF bridge. Powered on the computer and nothing on screen :eek:

then

as I realised that plugging in the monitor would help!

Arrived on the Windows 7 desktop in low resolution with Windows trying to install the second card. Dismissed the prompts and went ahead and installed a copy of Catalyst 11.8 on top of my current 11.8 preview drivers. Install went without a hitch but did have a couple more butt clenching black screen moments than a single GPU install

Rebooted, went into CCC and enabled the CF radio box, and that was that

Tried a few games from my collection and with the exception of DE:HR (which ran ok before, bar the freezing and crash to desktop :rolleyes:

I will save that until it is fixed) and GTA4 I am very impressed. BFBC2 runs at well over 120FPS most of the time and I have upped some settings like AA too

Noise wise I am very impressed. My system is no louder than before both idle and under load. The spacing on this board means the cards are only ~6c apart in Afterburner under gaming load for a couple of hours

Anyway, don't know why I posted this, twiddling my thumbs before BF3

~>Dg<~ · 28 Sep 2011 at 23:33

thinking of doing same myself and have same psu

not sure whether to sell my card get a 6950 or get another and go crossfire

setter · 28 Sep 2011 at 23:43

Very good slot spacing there, certainly helps with multi gpu setups. Crossfire/sli with older generation cards can be a pretty nice little upgrade, for not too much outlay.

Overslop · 29 Sep 2011 at 00:11

Did you put the crossfire bridge in after taking that photo?

Surveyor · 29 Sep 2011 at 00:14

Overslop said:
If you add a crossfire bridge (2 ideally) you should get a performance boost.

Unless things have changed now and I'm behind the times?

Using 2 bridges makes absolutely no difference to using 1.

But the OP does need to use 1.

I'm sure they must otherwise I don't think they could enable Crossfire.

Overslop · 29 Sep 2011 at 00:15

Dang, in before my ninja edit!

Are you sure using 2 bridges has no benefits? I remember some website doing testing which showed that adding a second bridge added a couple of FPS on average.

setter · 29 Sep 2011 at 00:16

Does the bridge make much difference in crossfire. Curious as ive only ever used sli, without a bridge (ive often forgot to put it in) there was no noticeable difference in performance.

d_brennen · 29 Sep 2011 at 00:39

Yeah i did add the bridge as I wrote above

took that pic just after plugging the card in. You'll also notice the fans are stationary, I added electricity too

Surveyor · 29 Sep 2011 at 00:52

Overslop said:
Dang, in before my ninja edit!

Are you sure using 2 bridges has no benefits? I remember some website doing testing which showed that adding a second bridge added a couple of FPS on average.

Not ninja enough

I've never seen anything which says using 2 bridges makes a difference. Quite the opposite and everyone says it makes no difference.

If you can find something that says different I'm happy to be proved wrong.

Andy__C · 29 Sep 2011 at 08:41

Good to read that this has given a real boost.........

I have one 5850 and am considering a 2nd soon once I get through the current batch of games that really only need one GPU (FO:NV, Morrowind Overhaul, etc....) and to play Skyrim, The Witcher 2 etc... as they were intended.

d_brennen · 29 Sep 2011 at 12:31

Can confirm, two bridges don't make a difference

Defunkt · 29 Sep 2011 at 14:08

will 2x 5850's be sufficient for BF3 1080p? Would be a great result if you can get a decent amount of fps in that for the extra minimal cost.

TC_Overclocker · 29 Sep 2011 at 14:18

Defunkt said:
will 2x 5850's be sufficient for BF3 1080p? Would be a great result if you can get a decent amount of fps in that for the extra minimal cost.

Unfortunately, whilst the GPU's can handle BF3 nicely... it's the VRAM that's letting it down. I have 2x 6870 1GB cards and it's the lack of VRAM causing me issues at 1080p (well 1920x1200).

The problem being at that resolution BF3 is trying to load 1.4GB worth of data into VRAM... as the cards only have 1GB, the rest is being loaded into system RAM and causing dramatic drops in FPS

Next on my shopping list is 2 cards with a min. of 2GB per card...

Defunkt · 29 Sep 2011 at 14:29

TC_Overclocker said:
Unfortunately, whilst the GPU's can handle BF3 nicely... it's the VRAM that's letting it down. I have 2x 6870 1GB cards and it's the lack of VRAM causing me issues at 1080p (well 1920x1200).

The problem being at that resolution BF3 is trying to load 1.4GB worth of data into VRAM... as the cards only have 1GB, the rest is being loaded into system RAM and causing dramatic drops in FPS

Next on my shopping list is 2 cards with a min. of 2GB per card...

Unfortunately I suspected the VRAM would be an issue with that game and the 1gb cards. Oh well, 2gb cards it will have to be.

d_brennen · 29 Sep 2011 at 15:37

Are people looking at afterburner for their VRAM usage figures? Just an FYI when I played Crysis before installing CF it showed 600+MB VRAM usage and 1200+MB after...

Martini1991 · 29 Sep 2011 at 15:45

TC_Overclocker said:
Unfortunately, whilst the GPU's can handle BF3 nicely... it's the VRAM that's letting it down. I have 2x 6870 1GB cards and it's the lack of VRAM causing me issues at 1080p (well 1920x1200).

The problem being at that resolution BF3 is trying to load 1.4GB worth of data into VRAM... as the cards only have 1GB, the rest is being loaded into system RAM and causing dramatic drops in FPS

Next on my shopping list is 2 cards with a min. of 2GB per card...

You're not at 1080p.
1080p I'm getting about 1900mb VRAM usage (Crossfire, so divide by two)

TC_Overclocker · 29 Sep 2011 at 15:48

Martini1991 said:
You're not at 1080p.
1080p I'm getting about 1900mb VRAM usage (Crossfire, so divide by two)

Sorry Martin, I don't understand... why do you say I'm not at 1080p?

I also thought the main problem with Crossfire is that it doesn't double what you have (i.e. 2x 1GB VRAM) so does it divide the VRAM usage between the cards?

Martini1991 · 29 Sep 2011 at 16:06

TC_Overclocker said:
Sorry Martin, I don't understand... why do you say I'm not at 1080p?

I also thought the main problem with Crossfire is that it doesn't double what you have (i.e. 2x 1GB VRAM) so does it divide the VRAM usage between the cards?

1080p is x1080, you're at x1200, ergo, not 1080p, you're higher, I think the specific is 1200p? 16:10 aspect ratio.

And VRAM doesn't double in Crossfire, but my 1GB 6870's are reporting total usage of 1950mb VRAM, so the true amount must be half of that.

Either way, very VRAM limited.

harmony · 29 Sep 2011 at 16:09

I have said many times that 1GB is a poor choice for SLI/CrossfireX under 1920x1200 in Year 2011. I guess BF3 will make the followers of 1GB learn.

elrasho · 29 Sep 2011 at 16:11

Im running BF3 Beta at 1680 * 1058 everything on High except Textures on Ultra and I get constant 80fps. Sometimes goes high as 110 then low as 50 when theres a lot of smoke. Im happy with that but about to create a new thread about overlocking my 5850s...