ATI ( AMD ) Crossfire X Explanations and Suggestions Please

[MidnightWizard]

Having recently acquired a MB that supports this
but
being DOF when it comes to new hardware.
I would appreciate it if one of the hard core gaming hardware guru dudes could explain some stuff to me.

Here is a graphic showing XFire support

Crossfire Combo Chart

Bit old now I think ?

I do not intend to use the rig for gaming but some other graphics intensive work.

As the MB only supports ATI XFire my GPU options are thus only ATI ( AMD )

Basically I am looking for a DUAL Head GPU that will support XFire but at a reasonable price ( not the top end )

From my reading it looks like I can install ONE GPU ( DUAL head ) and then install another GPU at a later stage as long as it is compatible with the already installed card

Is this correct ?

Also is it better to install two cards that are the same ?
or
Can you install a higher end and a lower end card together ???

Please explain and help out a non-gamer

Thanks

 

[Archer]

What programs will you be using?
What is your budget for a single card?
It is rare that you are able to install a lower card with a higher card, UNLESS that higher card is actually built on the same GPU which only really happens with dual GPU cards (top end) so you wont run into that.
And I admit, never heard of "Twin Head GPU" before. Are you referring to dual outputs? If so then every 5000 series card and up can run 3 screens on their own (some can do six) so there is not problem there. If it doesnt mean that then I'm

 

[MidnightWizard]

Dual Head

What is your budget for a single card?
It is rare that you are able to install a lower card with a higher card, UNLESS that higher card is actually built on the same GPU which only really happens with dual GPU cards (top end) so you wont run into that.
And
I admit, never heard of "Twin Head GPU" before.
Are you referring to dual outputs?
If so then every 5000 series card and up can run 3 screens on their own (some can do six) so there is not problem there.
If it doesnt mean that then I'm

Sorry meant "Dual Head" -- will correct

Multiple screens on ONE GPU is what I meant

Install one card initially that will support more than one monitor

As I understand the extra card in Cross Fire setup will just provide more processing power ????

What is the entry level price on a set up like this ( just wait until I have fetched my bottle of single malt )

 

[Archer]

I still need to know what programs you will be running (and your budget). I suspect many of them wont gain a huge performance boost with crossfire.
The absolute cheapest card that can run 3 screens is R500, but thats pushing it for anything other than excel. To make is useful I'd say you need ±R2k for a HD6870. For a bit more grunt get a HD6950 for ±R2800. Both those cards will run 3 screens, although iirc you will need an active displayport adaptor for the third screen (first two screens are normal DVI)

 

[TJ99]

Sorry meant "Dual Head" -- will correct

Multiple screens on ONE GPU is what I meant

Install one card initially that will support more than one monitor

As I understand the extra card in Cross Fire setup will just provide more processing power ????

What is the entry level price on a set up like this ( just wait until I have fetched my bottle of single malt )

Maybe I can help, I litteraly built my Crossfire setup 2 days ago.

Dual head is a (very) old name, it's now called Eyefinity, most ATI/AMD graphics cards these days have 4 outputs, usually 2 DVI, 1 HDMI and one DisplayPort. You can use any 3 at a time, for 3 displays. Some specialist (very expensive) cards support up to 6 displays each.

It's always (even now) better to have one better card than 2 cheaper ones, because it will likely use less power, and the extra performance will always be available (a few, mostly older, games etc aren't compatible with Crossfire.)

Yes, that chart you linked to is quite old. What I do know is that from the 5000's up, you can crossfire any two cards as long as they're from the same series, ie the first two numbers must be the same. For example you can crossfire a 5770 and a 5750. I don't know if they need to have the same amount of RAM, but I used two with 1GB each just to be sure.

Different manufacturers are fine, so you can do like I did, and buy one card, then later when your budget allows, and prices have dropped, add another one from the same series. This is what makes Crossfire better than SLI because you can combine quite different cards.

Edit: You should be able to get 2 midrange or 1 higher-end card for a little over R3000. Bear in mind though that you'll need a power supply that can handle the extra load, GPU's eat a lot of power, they're normally the biggest consumers in the system, and if you have 2, well... You probably need at least a 600W (name brand) PSU for 2 midrange cards.

 

[MidnightWizard]

Answers

I still need to know what programs you will be running (and your budget). I suspect many of them wont gain a huge performance boost with crossfire.

The absolute cheapest card that can run 3 screens is R500, but thats pushing it for anything other than excel.

To make is useful I'd say you need ±R2k for a HD6870.
For a bit more grunt get a HD6950 for ±R2800.
Both those cards will run 3 screens, although iirc you will need an active displayport adaptor for the third screen (first two screens are normal DVI)

Aaahh OK thanks

Application = Spatial // Mapping // GIS

Budget = As much as SO will allow

I see then that a "Dual-Head" card will have TWO DVI outputs / interfaces

 

[MidnightWizard]

Ferrari -- LOL

Edit: You should be able to get 2 midrange or 1 higher-end card for a little over R3000.
Bear in mind though that you'll need a power supply that can handle the extra load,
GPU's eat a lot of power, they're normally the biggest consumers in the system, and if you have 2, well...
You probably need at least a 600W (name brand) PSU for 2 midrange cards.

Aha -- I see that this is part of a process

Kind of like building a Ferrari -- and having no money left over for petrol

 

[TJ99]

Aha -- I see that this is part of a process

Kind of like building a Ferrari -- and having no money left over for petrol

Kind of... but I think you've got something wrong with the "dual head" thing there, that's ancient tech compared to the new cards really. They have a few (normally 4) ports, and you can use 3 at a time. Maybe you should read up on that first?

 

[Chevron]

I you use a 5770 with a 5750 the 5770 will be downgraded to 5750 clocks and whichever memory is less. Meaning if one card is 1gig and the other is 512, only 512 of the 1gig card will be used.

It's best to do two cards at once. That's if you want six screens. If you only want two screens then just get a 6870.

What power supply do you have?

 

[TJ99]

I you use a 5770 with a 5750 the 5770 will be downgraded to 5750 clocks and whichever memory is less. Meaning if one card is 1gig and the other is 512, only 512 of the 1gig card will be used.

It's best to do two cards at once. That's if you want six screens. If you only want two screens then just get a 6870.

What power supply do you have?

I'm not so sure about that downclocking thing hey:

http://hardforum.com/showpost.php?p=1035212799&postcount=2

Also, you can set each card's clocks and fan speeds seperately in the CCC so it doesn't make sense..

 

[MidnightWizard]

Some General Stuff

To make is useful I'd say you need ±R2k for a HD6870.
For a bit more grunt get a HD6950 for ±R2800.

The Six hundred series seems to be the latest ( and therefore the most expensive ? )

ATI/AMD graphics

Are the Five hundred series no good ?

Yes that Eyefinity looks awesome

EyeFinity

Silicon Graphics had something similar many moons ago.

There is another question .......

Can you use TWO monitors at the same time with CrossFire enabled ????

Power Supply -- I am still building up the system -- what do you recommend ???

 

[Archer]

Yes the 6xxx series is more expensive but it'll give you slightly better value actually. Feel free to go for a HD5870/50 but they'll be in the R2k range so might as well go for the newer stuff
With a single card you can get 3 screens max (some special cards can do 6). With crossfire enabled you can get 6 screens no matter what.
Power supply will depend on what you eventually get. I suspect you'll find a single HD6950 to be ample and hence a solid 500W will be enough. For crossfire you're looking at 600W+ depending on the card. Look at Corsair PSUs, they are rock solid, and not too expensive either.

 

[TJ99]

The Six hundred series seems to be the latest ( and therefore the most expensive ? )

ATI/AMD graphics

Are the Five hundred series no good ?

Yes that Eyefinity looks awesome

EyeFinity

Silicon Graphics had something similar many moons ago.

There is another question .......

Can you use TWO monitors at the same time with CrossFire enabled ????

Power Supply -- I am still building up the system -- what do you recommend ???

The 6000's are the latest yes. They're a bit faster than the 5000's but both are DirectX11 cards so they have the same features. The latest ones just have a bit of performance improvement, and I think use less power, so yes the 5000's are still good. Awesome in fact for the price. My two 5770's kick ass.

I don't know if you can actually use Crossfire with more than one screen, but for what it sounds like you want to do, I'd rather recommend just using 1 card anyways.

Power supplies - The Corsairs and OCZ's are pretty good value for money, get a 500W if you use a single card, or a 600-700W if you plan to upgrade to 2 later.

 

[MidnightWizard]

Educated

Thanks guys for all your help -- I am certainly a lot wiser now

Now to go and hit the "classifieds" ( Carbonite )

 

[MidnightWizard]

Brands

I'm Back .........


OK I see that there are a number of fabricators using the ATI chip sets

Which is the best brand to go for -- Saphire ?

Seeing as it is a Gigabyte MB perhaps a Gigabyte GPU ?

Those prices -- HHhhmmm -- fell off a bus

 

[Archer]

Doesnt really matter what manufacturer you go since they are all made exactly the same as per AMD design, unless its a factory overclocked version. Take the cheapest that has a 2 year warranty and thats that. If going second hand, I'd still take the cheapest. There is also zero correlation between the manufacturer of your motherboard and GPU. All versions will work exactly the same on all motherboards

 

[mass09]

Keep in mind : Some might have noisier fans than others..

 

[TJ99]

Doesnt really matter what manufacturer you go since they are all made exactly the same as per AMD design, unless its a factory overclocked version. Take the cheapest that has a 2 year warranty and thats that. If going second hand, I'd still take the cheapest. There is also zero correlation between the manufacturer of your motherboard and GPU. All versions will work exactly the same on all motherboards

Yep, it makes almost 0 difference, except:

Keep in mind : Some might have noisier fans than others..

The fans & heatsinks are the only real difference between them. And like I said, if you decide to add a second one later, it can also be from a different brand, I'm using a Sapphire and an HIS card in Crossfire at the moment. Just make sure the fans don't get too clogged with dust and you should be fine.

MSI or Gigabyte or ASUS cards cost a few hundred bucks more and you don't really get anything more for your money.

 

[Rock Bottom Computers]

HD6850

My 20cents

If you can, start your crossfire setup with an HD6850. The HD6850 retails at a good price of approx R1500-R2000 depending on which brand. (The ATI and Radeon names is going to expire due to AMD rebranding and in the near future and it will be called AMD Vision HD6850)
Have read on a Tom's hardware discussion that currently this crossfire setup is among the best in terms of value/performance.

Regarding mixing and matching different graphics cards. ...It can be done but it supported buy a very limited amount of motherboards. The MSI Fuzion springs to mind.
Remember to have a meaty powersupply to run two HD6850.