Sli or not to sli? 6 replies

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jimbo_0002

Yep

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2nd August 2007

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#1 8 years ago

Ive only bought nvidia cards don't know why just have now im building a new computer and i need a gpu, for some reason in my head I don't seem to like sli like I would rather a single high end card, Im not sure if its a price thing or not.

I have a few questions (I'm sorry but I havn't researched really anything on this yet)

What advantages and disadvantages does sli have? Is sli basicly the same a duel gpu card? Sli for gaming? Are some game not decustomised? Sli for 3D rendering/ video editing? Ive heard of micro stutter not sure what it is?

For my new rig i was going to get a 580 but the price in aus is $699 and i was looking at some benchs for it and i saw 460s sli getting the same speeds and the cost would be under $400, does the 580 have superiority in other areas? Then just basing my purchase on frame rates.

That's all i can think of right now, sorry for the long post, Ill probably think of other things later.

Any help/advice would be much appreciated.

Cheers




*Daedalus

A Phoenix from the ashes

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18th April 2006

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#2 8 years ago

Right.

Advantages: Performance, duh. Disadvantages: Micro stuttering (see below), and sometimes finicky drivers, though that's usually fixed pretty quick.

Dual GPU: I'm not sure of the finer details on this one. With the newer NCP I'm pretty sure you can set GPU A of a dual GPU card as PhysX and GPU B as workhorse, so I suppose in that respect they're similar.

It's also worth mentioning that with a dual GPU card you save on space. You gain two slots that you wouldn't otherwise have, though a 9800GX2 (8800GT SLI) will run hotter than two 8800GTs. Gaming: As I said above, some games don't scale well in SLI, but that's usually fixed within a couple of weeks. Right now, the 400 series cards have the best scalling, but I'm sure the 500 series will match it once they get proper drivers out.

3D Rendering: No clue on that one I'm afraid.

Micro Stutter: There are two different modes you can run SLI in. AFR (alternate frame rendering) and SFR (same frame rendering). In AFR:

GPU 1 - frame 1 GPU 2 - frame 2 GPU 1 - frame 3 GPU 2 - frame 4

The first GPU takes the odd frames, the second takes the even frames. Then there's SFR.

GPU 1+2 - frame 1 GPU 1+2 - frame 2 GPU 1+2 - frame 3 GPU 1+2 - frame 4

In this mode, each frame is split - based on graphics load, it's not 50/50 - and each GPU takes a chunk of the work.

In either mode, if one card gets hung up for a microsecond rendering a frame while the other GPU is waiting for it, you'll get a big dip in FPS - sometimes as bad as going from 40FPS average down to 10-15.

With recent GPUs though, microstuttering has become much better, especially the 400 series. Microstuttering basically isn't an issue because Fermi gets such great minimum framerates.

The general rule of thumb is to get the best single card you can afford, and upgrade to SLI later if you need/want to. You could always get two EVGA 460s and step up to a 4/580 when the prices come down a bit, though I'm not sure if EVGA's step is active in Australia.

As for superiority in other areas... not really. I mean obviously it's more powerful, and the cooler means that it would probably run cooler than two 460s, and be quieter, but they're the same architecture, so no card is better at one thing than any others.

To make you even more confused: clickie. :)




jimbo_0002

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2nd August 2007

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#3 8 years ago

Why thank you daed for taking the time and answering all my questions in a single post! checked out the link and it made me sad thinking im going to have to wait till Dec 13 to see what ati brings, I think if i cant wait ill probably just get the 580.

one other question came to mind, power supply if i do wait but get some parts before i choose a card what kind of min wattage should i look at for either 560s/580/6970-50 and maybe an sli for 580 in the future?




*Daedalus

A Phoenix from the ashes

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18th April 2006

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#4 8 years ago

The PSU you have now should be fine for any single card (I have the 1200W version, they're pretty good as far as ratings), but for SLI, I'd say at least 850, and that's for 460s, ideally 1kW.




jimbo_0002

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2nd August 2007

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#5 8 years ago

Alright cheers, I'm selling my entire rig so i wont be using current psu.




>Omen<

Modern Warfare

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1st January 2005

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#6 8 years ago

I agree with what Daed says above, and you're already headed on the right track if you're considering the 580. It's also probably best you wait to see just how well SLI improves with further driver development, and there will likely be holiday sales anyway. Hopefully there will be a marked improvement within that time.

On 3D rendering, I'm almost positive it doesn't matter whether you're referring to that which occurs in games or 3D modeling. SLI, esp GPUs that scale well in SLI, would def improve the horsepower you have to work with. However be aware that some 3D modeling apps are actually more RAM than GPU intensive.

The general rule of thumb is 3D tools that are wire frame and used for things like architecture are very RAM intensive, and those which can produce 3D images are very GPU intensive. Any of the higher end Fermis should be able to handle such things just fine, esp in SLI. A dedicated workstation card like the Quadro might do it a bit better, but they're damn expensive and aren't made for gaming.




jimbo_0002

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2nd August 2007

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#7 8 years ago

I was asking about rendering as I was doing a school course in Multimedia which involved 3D modeling and such and no i have finished but i would still like to dabble in it, but mainly its going to be a gaming rig. Maybe if i get into the industry ill make a workstation with a Quadro and claim it on tax