SLI : Pros & Cons

[Astrotoy7]

If you're into gaming hardware, you would most likely have your own take on what SLI(and ATIs crossfire) is and if it's worth the trouble

Im not going to go into what SLI is... there are zillion places you can learn about nvidias Scalable Link Interface technology - including the official site

Great tech discussion article about SLi at Hexus.net

Nvidia's official spiele her at SLI zone

If you want something a bit more general, the SLI Wiki isn't too bad.

Having beta tested vista drivers(pre release) for SLI, having used a SLI based PC in xp gaming with the 7950GX2 - Ive had a bit of experience with it.

I will give a summary of pros and cons from what I experienced - it will be interesting to hear others take on it:

Pros:
*Optimised for high resolution gaming - with high end games. As someone with a 1600p monitor, the idea of running a game super smooth at 2560 x 1600 with all effects maxed it quite appealing.

This is where SLI has been *proved* to shine.

Over @ AHTO, NegSun and I were discussing the 7950GT -which is still a decent DX9 card.

There is a super article here - showing what SLI can do with the the 7900GTX
http://techreport.com/articles.x/11686/6

To give a sample of what you will see - have a look at these numbers for FEAR. Can you really argue that SLI is pointless in an ultra hi-def context ? I think it is quite difficult to !!



*More games recently with SLI optimisations... most 'next gen' high end PC games will include them as standard
*If you have a compliant mainbaord - 2 older cards will get you more longevity. Look at the numbers for the 7900GTX in SLI !!

Cons:
*power - 2 cards suck more juice than one
*heat - due to the above

Although most people that build SLI rigs have thought about thermals well in advance, so work to minimise this with extra fans, watercooling etc

*Cost. Especially if you want the *new* stuff. eg. an 8800GTX Ultra SLI setup will cost you the price of a small (used) car

*Games - there hasnt been a huge amount of games that have SLI enhancements. I mainly remember enabling it in COD2.

*DX10 shift and Drivers - SLI was only recently enabled in a WHQL driver release for the 8 series GPUs. With devs and the manufacturers playing catch-up with Vista, tech wise - we are currently in a DX9-10 limbo - which is quite unusual

What I find annoying is that the manufacturers keep thundering on releasing new tech where the full potential of existing tech hasnt been properly flashed out. eg. The nvidia 9 series GPUs are due late this year, early next year.... They are nowhere near maximising the potential of the 8 series - they should slow down a bit and concentrate on making great drivers for what is already around... IMO anyway

x64 operating systems have also not been exploited to their full potential.... it is comical to think that 64 bit CPUs are standard now...but they are almost always sold in an x86 platform. Whilst I am pleased Vista x64 is quite stable, it is merely because MS has done a great job developing x86 emulation in Vista 64....

The ideal pc standard for high end gaming:
*Quad Core CPU
*SLI/X-fire capability or high end single GPU
*x64 OS
*Bluray or HD-DVD drive

currently, we only get close on one of those...the gfx card. I think there are a good few years before there is an x64 shift in the gaming world... it definitely is for the better...because the high end hardware that is coming will need to be backed up by the ability to play with over 3GB of RAM...

time will tell, and our wallets will suffer

mtfbwya

[Det. Bart Lasiter]

Another con I've noticed is that some games don't play nicely with SLI. I remember before Oblivion got patched I'd get random crashes or a lower framerate with SLI enabled.

[Negative Sun]

One of the major cons is the fact that it would cost you even more to get a new PSU, which doesn't come cheap above a certain amount of Watts...

I'm interested in getting a Crossfire and AM2 mobo, as I feel it would be quite futureproof with AM2+ and AM3 chips being backwards compatible with AM2 mobos, not to mention the fact that (as mentioned in another thread) Sapphire has just launched a dual DX10 Radeon card which should be quite interesting, especially to achieve those higher framerates at high resolutions

[Q]

My main problem with SLI/XFire is that by the time you're ready to buy the second card, your first one's obsolete.

It's best for those who plan on buying them both at the same time. As an upgrade, It would probably be wiser to just buy the next generation card.

[Astrotoy7]

Originally Posted by Qliveur

My main problem with SLI/XFire is that by the time you're ready to buy the second card, your first one's obsolete.

It's best for those who plan on buying them both at the same time. As an upgrade, It would probably be wiser to just buy the next generation card.

Im 100% with you on that Q. Perfect example - If i'd kept the 7950GX2 and got another one....sure a 2gb framebuffer and 4 GPUs to brag about..... but it would absolutely devour power like nothing else.... to get comparable performance to one 8800GTX on its own.

With the G90 series not far off, Im not bothering even thinking about an SLI config(although it wouldnt fit in my shuttle rig anyways!)

@NegSun.... dude, youve been around here long enough to know THERE IS NO SUCH THING AS FUTURE PROOFING IN VIDEO CARDS

The new product turnover is just way too high...

once again - it all really depends on what you want to do and at what rez. Once my 8800GTS 640mb starts to labour on the new games I want to play at 1080p + then its time for an upgrade !!

mtfbwya

[Negative Sun]

Originally Posted by Astrotoy7

@NegSun.... dude, youve been around here long enough to know THERE IS NO SUCH THING AS FUTURE PROOFING IN VIDEO CARDS

I was meaning more in the sense of the mobo and CPU, but then again, with PCI-e 2 on the way, even the mobo will be outdated soon enough...

As for the GPU, I agree, as long as it does what you bought it for, then that's all good (heck I'd be happy with a 512Mb X1550 AGP card atm!)

[stingerhs]

well, i've never been a big fan of Crossfire or SLI simply due to power requirements, cost, and the relative lack of a major performance advantage. yes, there is a performance advantage, but its not enough of an advantage over a single card solution. heck, with most games, there is little or no performance advantage since they're not coded to take advantage of multiple GPU's.

IMHO, its overhyped and overpriced.

[Astrotoy7]

Originally Posted by stingerhs

IMHO, its overhyped and overpriced.

hype might be one thing, but its not that commonly implemented outside the overclocker circle. I would love just one 8800GTX....

I do hope those games that **will** test out systems will hurry up though. I'm looking forward to gawking at Bioshock and Crysis on my monitor

mtfbwya

[Negative Sun]

Originally Posted by Astrotoy7

I do hope those games that **will** test out systems will hurry up though. I'm looking forward to gawking at Bioshock and Crysis on my monitor

Or make sure it's not a slideshow