To SLI or Not to SLI - that is the question?

[Crazy Buddhist]

OK guys and girls. Theoretical question here with practical implications:

You're MOBO is SLI capable and you have a budget of a) $100 b) $250 c) $400 for the Graphics card(s).

Which will give you a better overall system and/or graphics performance at any of these budget levels:

1) Buying the most advanced card you can with all your budget

or

2) Splitting the budget in half to buy a pair of (lower spec) twins and SLI-bridging them.

Also does it depend on what you are doing with the machine?

CrazyB

[Cymae]

sigh. this is the thrid time i'm explainigng this.

SLI does this: It splits the rendering on your monitor between two cards. you can only ever have one monitor with SLI. It should improve performance to 150% roughly. This is ONLY good if you a) have a massive monitor (22" widescreen I'd say is the absolute minimum), and b) if you do alot of rendering or high end graphics animation, and you want to speed up your rendering times. So unless you're a budding graphics artist with a massive monitor, do yourself a favour and buy ONE video card. Then at least you can go dual monitor sometime

[jdbnsn]

In my opinion, you are better off with a higher end single card than SLI these days. Many of the bench tests I've seen show the 8800 performing better than CF or SLI (hard for me to admit having CF myself). This will ultimately consume less power (I think) and you will have less difficulty getting all of your games to play. I have several games that won't budge with Crossfire enabled.

[jdbnsn]

So unless you're a budding graphics artist with a massive monitor, do yourself a favour and buy ONE video card. Then at least you can go dual monitor sometime

I disagree with that last part. you can run up to 4 monitors with good resolution with any of the CF or SLI enabled cards. You just can't run them with SLI or CF enabled. Using one monitor per port works fine in regular mode.

[Cymae]

can we sticky some sort of "What SLI and CX does" thing? this question has been asked like..twice in the last day or 2

In reply: i was reffering to enabled. not just having them

[Crazy Buddhist]

It splits the rendering on your monitor between two cards. you can only ever have one monitor with SLI.

Yes the first part I know.

I do lots of very heavy 3D rendering which is why I am asking the question.

The second part, Cymae, your information is incorrect. It depends on the MOBO implementation and cards: Sometimes (usually) the output ports on one card get disabled with SLI. So if you have 2 x SLI cards with dual output you will be able to run two monitors off of the one card who's ports are left functioning.

[Cymae]

yes..but it defies the whole point..you have 2 cards in SLI sharing the rendering on the monitor. If you add 2 monitors you mght aswell render 1 monitor per card...don't you think?

[Crazy Buddhist]

In my opinion, you are better off with a higher end single card than SLI these days. Many of the bench tests I've seen show the 8800 performing better than CF or SLI (hard for me to admit having CF myself). This will ultimately consume less power (I think) and you will have less difficulty getting all of your games to play. I have several games that won't budge with Crossfire enabled.

Thanks Jon. Thats helpful. I don't play games at all however. The 3D rendering I am doing is taking medical DICOM images from MRI and CT scans and rendering 3D models of the skeleton and various other body parts (gooey stuff )

My CPU is maxing out constantly and I would like to shift more of that load to the GPU(s?), although also planning to upgrade the CPU to a dual core Opteron 180. There are several variables in working out how to invest any spare £££ I get into best improving performance - this one was playing on my mind.

CrazyB

[Crazy Buddhist]

yes..but it defies the whole point..you have 2 cards in SLI sharing the rendering on the monitor. If you add 2 monitors you mght aswell render 1 monitor per card...don't you think?

Thanks Cymae. I intend to stick to one monitor and don't see myself ever needing two. It's merely about 3D rendering performance (not for games) and where to best invest to improve that.

CrazyB

[Cymae]

then yeah. I'm hoping to get a 22" and then upgrade to CX. its feasable