Eyefinity - 2x 5970 CF vs 2x 6970 CF for 3x1 monitor setup

[zeddius]

Hi gents (and ladies )

I have been searching a lot of forums for some hints as to what to buy, and i was hoping to get some input from this community since many ppl have refered me to this place.

USE My goal is to play new games at 5700*1200 (3x 1920*1200 24" monitors). Most importantly, the reason i decided to try eyefinity is Battlefield 3. So i need a setup that would probably let me run BF3 in eyefinity at high settings with a smooth FPS.

My first dilemma is what GPU to use. I currently have a single HD 5970. With this card i have been able to play approx. every game i come accross maxed out on a single monitor. I would guess though that a single 5970 may struggle abit with newer games in eyefinity.

Do the question is, should i buy a 2nd 5970 and crossfire (or 4xCF as some say since each card has 2 GPUs), or should i go for 2x 6970 CF.
-5970 CF seems to beat 6970 CF in many reviews
-5970 only has 1 GB per GPU, compared to 2 GB for the 6970
-Some reviews claims that the 5970 is better then 6970 at higher resolutions
-Some ppl say that 4way CF (2x5970) is problematic in eyefinity

I have just also started to consider a Powercolor HD 6990, so my choices are as below with prizes (though in Norwegian money, but you can see the difference.

1) 2x 5970 CF - Need to buy 1 new 5970 for 3400 NOK
2) 2x 6970 CF - Need to buy 2 new 6970 for 5200 NOK
3) 1x 6990 -Need to buy 1 new 6990 for 5000 NOK

[wagoo]

I would honestly just try it first on your existing 5970. Your main issue is going to be running out of VRAM with only 1GB I suspect.. buying another 5970 for 4x crossfire wouldn't help with that at all.

If you do find 1GB is too limiting, then a 6990 seems the obvious choice (if you can find one in stock anywhere!)

[Downtown1]

Well, getting a second 5970 seems to be cheaper up front ($500 vs $700-750), however are you going to have a rig powerful enough to take advantage of it? You will need an insane power supply and a motherboard that has 2 PCIe x16 lanes. Also now you're doing 4X crossfire which may not always be well optimized going forward (remember, they basically don't care about 5xxx series anymore since they are 1 gen old).

[zeddius]

I got the power to run 2x5970 (corsair 850W), but the MB is the P55 type with one PCIx16 and one PCIx8. Dont know if this will have any significant impact, though i guess i should assume some performance drop compared to having 2x 16 PCE slots

[Bluesilentpro]

I wouldn't bet a Corsair 850W would power a 5970 Quadfire with an oced 4GHz+ CPU (which is recommended for so much GPU-power) under heavy load. But it was already mentioned that gpu-power is not the problem but VRAM. With a 5970 Quad I assume you would like to get maximum quality and much AA & AF. That is where 1GB of VRAM per card ist just not enough. So you might have huge framedrops despite having insane gpu power. I would definitely prefer a 6970 2GB CF.

EDIT: 16x or 8x PCIe doesn't matter that much. Thats the difference for 5870 CF with a 3.5GHZ 980X:



Its a mere 2-4fps. It won't change that much with 5970s or 6870s. ;)

[zeddius]

Thx for the reply.

With regard to power, i checked the power consumption through "extreme power supply calculator" and it recommended a 750W PSU. Ill hope the 850 is sufficient.

Back to the GPU, i had actually ordered a 2nd 5970 which i got today. I have it installed now and doing some testing. I dont see any performance increase on games like crysis and crysis 2, but that is to be expected i guess since i have read several places that these games dont scale well. I also tested with metro 2033, and this was a positive surprise. With a single 5970, with all settings on max, i had an FPS from 40 to 20 during the first part of the game. I then activated crossfire with 2x5970 and tested again, and the FPS was from 80 to 40 for the same sections.

Anyways, i am also concerned with VRAM and only 1 GIG on the 5970. I am actually considering returning the 2nd 5970 i bought for a full refund, sell my primary 5970 on the used marked, and order a new 6990. There is a web shop were i live which will get some of these in stock within a couple of weeks. Im not sure yet though, but if 1 GIG VRAM will prolly be a limiting factor in the next couple of years, i guess i might aswell do this.

[Downtown1]

There are 2GB 5970s (I have a 2GB 5970), not sure why you bought the 1GB.

But I guess if you only have a 8x second PCIe lane you really should just get the 6990. Otherwise you will see a performance drop vs using 2 cards.

[zeddius]

Hmmmm, to be honest, i really dont which version of the 5970 i have. It says 2 GIG on the vendor page, but i have always assumed that this is the total, as in 1 GIG for each GPU on the card, so a total of 2 GIG but 1 GIG effective mem per GPU. Perhaps you could help me clarify this. These are the links for the two 5970 i have:

Powercolor : http://www.komplett.no/k/ki.aspx?sku=614245#extra
XFX : http://www.komplett.no/k/ki.aspx?sku=518743#extra
- Manufacturor link : http://xfxforce.com/en-gb/products/graphiccards/hd%205000series/5970.aspx

The 5970 is listed as a 2 GB card, the 6970 as a 2GB and the 6990 as a 4 GB card. I have always assumed this means that the 5970 with 2 GPU has 1 GB per GPU, the 6970 with 1 GPU will have 2 GB effective mem, while the 6990, with 2 GPUs will have 2 GB per GPU, same as for the 6970. Please clarify if i am wrong.

[wagoo]

Right, 2GB in this case means 1GB per GPU. Which is all that matters.

[stangflyer]

Don't know if its to late but I have the answer for you. I have had a 5970 for 1.5 yrs. Use it 3318x1680 which is the same as 5040x1050 in landscape mode. I think I even run out of vram on some games.

I have a friend that let me use his 6950 crossfire cards to try while he was out of state on vacation. I oc'd the cards to a little higher than 6970 clocks.

The 6950 were much better than my 5970 because they scale at 85-90% on average and the 5000 series is only 45-60% scaling.

I have thought about getting another 5970 but have read the horror stories on 10-20% scaling over the first 5970. Also some issues with worse performance using 2 5970's over .

Get the 6970's.

[ViciousXUSMC]

I would go 6000 series for crossfire simply because its less demanding for power and produces less heat so it will be much easier for the system to handle it without having to go crazy with tons of fans and a huge power supply. The 5870 beats the 6970 head 2 head but when you have 2 cards the difference is really not as big of a deal anymore because as long as you have enough power to get 60fps steady thats all you need.

I suppose the general opinion is 6000 series scales better than 5000 series but I think the cards work much the same, I wonder if most of that knowledge is simply based on the fact that newer and much better drivers are out now than we had when the 5000 series was new.

[BHawthorne]

6970 > 5970 simply for the fact of PSU requirements and the scaling on 2 is better than on 4 GPU for the money.

[stangflyer]

6970 > 5970 simply for the fact of PSU requirements and the scaling on 2 is better than on 4 GPU for the money.

+1 on this, Like I said I have tried the 6950's. I also have a friend that has the exact same system I have except he does not have eyefinity and he has a 5870. If I clock my 5970 to 5870 speeds and play 6-7 games on a single screen I am averaging about 50-55% scaling using same graphics settings he is. If I got even 80% I would be as very close to a 6970 crossfire. Most of us know that a 5870 is almost as fast as a 6970 in a single card. It is just the scaling is what hurts the 5 series. We are both on the 11.8 preview drivers.