2 heads are better than one...

[Dillgaar]

but are two cards better than one...

would 2 SLI cards working in unison produce a better, or more efficient work load then one larger card?

I am trying to figure out if I should buy one huge card or split the cost and buy 2 smaller ones

Any tips?

[Fozzik]

No.






hehe... ok, I'll say more.
One higher-end card is always the better bet. The only time I would recommend anyone buying two video cards at the same time is if you are going to get the highest end cards on the market, and SLI is the only way you can gain any more performance. Otherwise, it's always better to get a single, newer card.

Not just because it has more consistant performance across all games, but also because SLI really only increases straight frames per second. All the fancy shading and effects are still done on each card separately, the memory of each card is still separate... etc. Right now it's especially true, because you are probably choosing between two cards from last generation (i.e. 6xxx-series) vs. one card from this generation (7xxx-series). In cases like that, it's even more in favor of the higher-end card, because you are gaining actual hardware features... things like transparency anti-aliasing...which no amount of 6xxx-series cards is ever going to get you.

Also, buying an SLI motherboard and a single high-end video card means that next time you want to upgrade, you will have more options. Either get a second card just like yours for more straight performance... or a new high-end card. Options are always good.

[Breogan]

I agree with Fozzik. Unless you are going for the top of the line setup with dual 7800GTX or similar, you are better served with a single faster card. The single card runs cooler, consumes less power, and has an equivalent perfomance to a dual 6800GT SLI.

The whole "if you want to upgrade you only have to plug another card" doesn't cut it for me either, since you can sell your old card and buy a new model paying a relatively small plus.

Example (talking about european market, not sure about the current prices in the US):

You have a 6800GT and want to upgrade. You have the option to buy another card to do SLI for a bit less than 300€ (and a new PSU if you don't have a SLI certified one), or you can sell the 6800GT for 225€ and buy a 7800GT for 375-400€, which means you'll actually be paying just an extra 150-175€ over what you got from the old card.

[Dillgaar]

can you have 2 different cards running SLI?

so for example I buy a 7xxx card and install it then a couple years down the line I want the performance of the new 8xxx cards can I get an 8xxx and still keep my 7xxx or will that hinder my performance? would it increase performance at all?

[Elrar (of Silky Venom)]

can you have 2 different cards running SLI?

so for example I buy a 7xxx card and install it then a couple years down the line I want the performance of the new 8xxx cards can I get an 8xxx and still keep my 7xxx or will that hinder my performance? would it increase performance at all?

The cards have to be indentical :)


(fozzik can get into the technical mumbo jumbo) :)

[Breogan]

SLI(nVidia) requires both cards to be the same, but CrossFire(ATI) allows you to use different cards as long as they are from the same generation: you can use a X800 and a X800XT together. The downside is that the perfomance of the fastest card will be reduced to match the slowest card's, which makes it nearly worthless.

[Dillgaar]

so it doesnt look like ti will be much benefit in an case... at least not it its current form... good to know

[Orlun]

What about this beast?

http://www.extremetech.com/article2/0,1697,1872312,00.asp

SLI without the Mobo.

Now, can you install two of those in an SLI computer for quad 7800's? :D

[Breogan]

I don't think it'd be a good idea to buy it, even if you have the chance to get one, since it'll be limited to 2000 units.

Pros: The card uses a dedicated external power adapter, so you won't need a SLI certified PSU.

Cons: You still need a SLI capable motherboard to run the card, and not all models have been certified.
It needs special drivers from ASUS since the suport in the ForceWare drivers is rather buggy.

[Gurf]

Ok, say I buy a totaly SLI ready system but stick with one card for now. I'm strongly considering the Gainward 7800GTX Golden Sample wich is clocked at 470 MHz core frequency (standard is 430 I think).

After two years I decide that it's time to go with an SLI setup of 7800GTX's, but now the GS version is out of stock or maybe I can get a much better deal on a 7800GTX card from another manufacturer.

So my question is, how will two cards of the same series but diffrent core frequencys perform in SLI? Or rather, does core frequency affect SLI performance?

Wonder if that made any sence... :rolleyes:

[Fozzik]

If I'm not mistaken, Nvidia is in the process of building more support into their drivers, which will enable the type of functionality you are describing (they may have done so already). It should allow you to use two cards from different manufacturer's, and maybe adjust their clock speed independantly.

[Fozzik]

Speaking of which... :D

http://techreport.com/onearticle.x/8926


They released the certified version today... not only does it include support for mixed-vendor SLI, but also performance improvements and some kind of optimizations for dual-core.

[Gurf]

Wow thank you so much for the info, you're a star! I think that was the last thing I wanted to check before I invested. Empty bank account, here I come!

Here is the info on mix and matching cards if anyone else is interested:

Example: You can use a GeForce 7800 GTX from manufacturer ABC with a GeForce 7800 GTX from manufacturer XYZ.
Note: You must still use two graphics cards that have the same GPU. For example, a GeForce 7800 GT must be matched with another GeForce 7800 GT (not with a GeForce 7800 GTX or a GeForce 6800 Ultra).

Mix and Match Graphics Cards with Different Input/Output Ports
Example: You can use a GeForce 6800 GT with Dual DVI & TV-out with a GeForce 6800 GT with Dual DVI & VIVO.

Mix and Match Graphics Cards with Different Clock Speeds
Example: You can use a higher clocked GeForce 6600 GT 550/525 with a standard clock GeForce 6600 GT 500/500.

Mix and Match Graphics Cards with Different Memory Sizes
Example: Using Coolbits, you can use a 128MB GeForce 6800 GT with a 256MB GeForce 6800 GT.

Note: NVIDIA recommends that SLI customers, whenever possible, purchase graphics cards with matching memory sizes. When dissimilar memory sizes are enabled to work together using Coolbits (value set to 18), the effective memory size for each card becomes the smaller of the two memory sizes.