to SLi or not

[jollyFE]

looking for input....which would be better? spend say 400$ on 1 vid card or $200x2 on 2 cards and sli them ..................I have heard that sli doesnt really add much.  is this true?

[Ghosth]

I still have not seen anything definitive that shows where SLI or crossfire adds more than 10 - 20% in most games or applications.

Much better to buy a 300$ card instead of 2 200$ cards. You can save yourself a 100$ and still get better performance.

[jollyFE]

sweet...sounds good

[eagl]

Best advice I've read was to buy the fastest card you can afford now, and then SLI them in a year or two when prices have dropped for the second card, when you might actually need the extra graphics performance.

[Tinribs]

not all games are sli compatable aces being one that isnt, you will get horizontal tearing if you run the game in sli.The nvidia control panel has recomended settings for the game where its also possible to set your cards up for sli anti alaising if you want.Ive done this myself I have it switched off in game and run my cards at 16x it works well and gives some benefit to running sli in a non compatible game.I dunno anything about crossfire but imagine this would not be a problem.eagl is right tho get the best single card you can afford and take it from there.

[Skuzzy]

It is not up to the game to be SLI compatible.  It is up to NVidia to supply a proper SLI configuration file for the game.  They do supply one for Aces High, but it is not that great.  It also forces vertical sync off, which is a bad thing for the game.

Applications/Games have zero control over SLI/Crossfire compatibility.


eagl's advice is pretty solid.

[Tinribs]

It is not up to the game to be SLI compatible.  It is up to NVidia to supply a proper SLI configuration file for the game.  They do supply one for Aces High, but it is not that great.  It also forces vertical sync off, which is a bad thing for the game.

Applications/Games have zero control over SLI/Crossfire compatibility.


eagl's advice is pretty solid.

I could have been a bit clearer in my reply of course Skuzzy is right as usual.

[Bino]

As a follow-up to the original question: 

How do NVidia's SLI and AMD's CrossFire compare?

[Chalenge]

Anandtech has comparitive benchmarks you can use to measure the relative perfomances. Notice that ever since the 2## cards SLI has been better than the 10-15% performance increase everyone talks about. You can use this to compare the cards ATI versus Nvidia or ATI versus ATI etc.

http://www.anandtech.com/bench/Product/166?vs=167

Of course if your still using an AMD Athlon 64 4800+ your CPU will choke the benefit and likewise for a x16/x8 SLI MB. In some cases you will see the reported frame rates climb more than 100% above a single card but I have been told thats not really 100% scaling. Im going to take it anyway. 

[Tinribs]

Another point to consider is that running sli limits you to only 2 memory slots, in a lot of cases this means more money for larger or faster sticks.I forgot to mention this before and its probably the most important factor.

[Chalenge]

I never heard that one before. Every system I have is using four slots to six slots without a problem.

It is true that some motherboards have problems running four slots and remain stable (ASUS P5N-E) but thats an issue of the motherboard and not SLI. Makes me wonder why they even put four slots on the board.

[columbus]

i am curious how much does running triple of quad SLI actually speed up your graphics? i heard SLI only gives you like a 5-10% increase, does triple give you 10% over that or a additional 5-10% added?

[Tinribs]

I never heard that one before. Every system I have is using four slots to six slots without a problem.

It is true that some motherboards have problems running four slots and remain stable (ASUS P5N-E) but thats an issue of the motherboard and not SLI. Makes me wonder why they even put four slots on the board.

dunno.

[TilDeath]

Another point to consider is that running sli limits you to only 2 memory slots, in a lot of cases this means more money for larger or faster sticks.I forgot to mention this before and its probably the most important factor.

I have built quite a few systems running SLI, Tri SLI and even one quad system,  I have yet to find an issue with memory slots be it 4 or 6 running more then a single card.  Please tell me where you are referencing your statement from.

TD

[Chalenge]

i am curious how much does running triple of quad SLI actually speed up your graphics? i heard SLI only gives you like a 5-10% increase, does triple give you 10% over that or a additional 5-10% added?

If you visit Anandtech at the link I posted you will see its more like 65-99% (in one case at least 100.2%) for the second card. The actual benefit depends on things like your CPU and the app/game your running. The only game I have seen that actually benefits from Quad SLI is FSX but sure there must be others! The only thing (I think) is that the CPU begins to hold back the benefit after awhile. For instance with FSX I was getting 36 FPS with 8800s but I didnt have a lot of addons added on and I had things like shadows turned off. Once the 295s came out I added more addons and started moving traffic sliders up to 100%. I was able to get the old settings up to 48FPS but in the end I added things and I was back down to 36 FPS which in reality is realy really good with FSX. The when the 480s came out I went tri-SLI and turned everything on and FPS went like this: 1 card - 22 FPS   2 cards - 39 FPS  3 cards - 56 FPS which would make you think its pretty close to 100% scaling but I am convinced the MB/CPU/RAM is still holding it back.

5-10%? Thats back before the 2## series came out but even then it was more like 33%.