SLI vs Crossfire

[Guest]

Hey guys
Just wondering something...
I'm still not convinced about whether to go with AMD or Nvidia graphics cards...
What's better? Can I use two different cards in SLI or Crossfire? If I buy 1 card, then decide to upgrade later, what steps will I have to take? Can I just add another card to my first one and run an SLI or Crossfire setup?
Sorry I'm so confused...
Also, what about overclocking? I was contemplating either a single GTX 660 Ti overclocked, or two GTX 660s in SLI, or a single overclocked HD 7950, or dual 7850s in Crossfire. Say if I buy one GTX 660 Ti, what do I have to do to run dual cards in SLI? Is it just like - buy the identical card again and just plug it into the motherboard?
Of course, I know that I'd need a bigger power supply... I understand that...
I play BF3 lots - that's the reason for these questions.
Thanks if you can help!
Sam

 

[Gate9er]

Hi

First of all NO you cannot run two different graphic cards in SLI nor in Crossfire X. This is because both cards will run with the specifications of the slowest/least powerful card. Furthermore, it depends how much are you willing to spend. AMD cards are a bit better when it comes to overclocking (mainly due to their cooling systems installed). Most of the AMD cards have 2 or even 3 fans installed on board.
In order to run an SLI using two Nvidia cards, you just have to buy two cards of the exact model, put them on your motherboard and just connect them using an SLI bridge (usually included in your motherboard's box, if your motherboard supports SLI configuraiton). The same stands for Crossfire X.

If you play just BF3 only, there is no need of going for SLI or Crossfire X configuration. Even a GTX580 can run the game in ultra high settings. If you have any questions please ask..

Hope this helps!

 

[17seconds]

If you want to run GTX 660 Ti's in SLI, make sure your motherboard is "Nvidia SLI Certified", otherwise it won't work. Make sure you have good case airflow if you are overclocking.

I would go for the Nvidia SLI option as they do a better job with multi-card drivers. Crossfire has been known to suffer more from stability issues and AMD takes longer to provide new game support. Also, there have been some recent tests showing that SLI does better with frame latency than Crossfire, meaning that gaming feels smoother with SLI.
http://techreport.com/blog/24415/as-the-second-turns-frame-captures-crossfire-and-more
http://techreport.com/review/23981/radeon-hd-7950-vs-geforce-gtx-660-ti-revisited
http://techreport.com/review/24218/a-driver-update-to-reduce-radeon-frame-times

 

[steddora]

Just thought I'd toss in my couple cents here.

Coming from a pair of GTX 550Ti's, don't do it unless you have to. Going with a single power house GPU is always going to trump SLi or CrossfireX. Simply put, microstutter is a curse. I recently tossed my 550's out the door for a single 7950. The 7950 isn't a giant leap in performance from the pair of 550's I had. It's about equal to upgrading from a GTX 580 to the 7950 as my GTX's were overclocked pretty decently. However, the biggest noticeable factor is that all of the microstutter is GONE.

Let me shed some light.. Take a game like BF3. I'd run most of all the settings at Ultra aside from the higher AA modes as the 550's suffered when using AA at high scale due to the lower memory and memory bandwidth. However, when I saw 60FPS against the frame limit it would look smooth and pretty sweet actually. Once it started dipping into the 40's in big firefights; it seemed like stuff was just stuttering like low framerates would. This happened often and it really doesn't matter what game. If the framerate wasn't bouncing off the limiter; it would stutter. Now it's not completely unbearable; but notable.

Now with the single 7950 in this rig, the same games are absolutely amazing and even if I do manage to make this card drop under 60fps; there isn't any notable stuttering until the 25fps range. This is due mainly to latency as the cards work together where a single card reduces this latency greatly.

Am I totally against SLi/CrossfireX ? Absolutely not. I'll probably Crossfire this card in a couple of years if I want a cheap boost in performance until my next card. However I won't ever make the mistake of rolling two GPU's to save money over the higher end cards.

Originally the two 550's together perform in the same class as the 570, and even beats it in some areas. When I purchased the two I had, I saved about $40 when compared to the 570. Was it worth it? Absolutely not, as the stutter is noticeable and if you're like me, it's irritating.


However, to answer your original question... You need the following to complete a SLi or CrossfireX configuration.

Two cards of the same model (I believe AMD cards can be the same family i.e. 7950 and 7970).
Motherboard that supports SLi/CrossfireX
Power Supply that can handle the cards/system.
SLi or CrossfireX bridge

If you're debating on the 660ti, it is a great card, and I've used one personally. Only thing I'd suggest; if you can swing the extra for a 670; it is worth it when it comes to AA and high resolution. The extra memory bandwidth makes the 670 shine over the 660ti. Either way, the 660ti is a decent card.

 

[Guest]

Just thought I'd toss in my couple cents here.

Coming from a pair of GTX 550Ti's, don't do it unless you have to. Going with a single power house GPU is always going to trump SLi or CrossfireX. Simply put, microstutter is a curse. I recently tossed my 550's out the door for a single 7950. The 7950 isn't a giant leap in performance from the pair of 550's I had. It's about equal to upgrading from a GTX 580 to the 7950 as my GTX's were overclocked pretty decently. However, the biggest noticeable factor is that all of the microstutter is GONE.

Let me shed some light.. Take a game like BF3. I'd run most of all the settings at Ultra aside from the higher AA modes as the 550's suffered when using AA at high scale due to the lower memory and memory bandwidth. However, when I saw 60FPS against the frame limit it would look smooth and pretty sweet actually. Once it started dipping into the 40's in big firefights; it seemed like stuff was just stuttering like low framerates would. This happened often and it really doesn't matter what game. If the framerate wasn't bouncing off the limiter; it would stutter. Now it's not completely unbearable; but notable.

Now with the single 7950 in this rig, the same games are absolutely amazing and even if I do manage to make this card drop under 60fps; there isn't any notable stuttering until the 25fps range. This is due mainly to latency as the cards work together where a single card reduces this latency greatly.

Am I totally against SLi/CrossfireX ? Absolutely not. I'll probably Crossfire this card in a couple of years if I want a cheap boost in performance until my next card. However I won't ever make the mistake of rolling two GPU's to save money over the higher end cards.

Originally the two 550's together perform in the same class as the 570, and even beats it in some areas. When I purchased the two I had, I saved about $40 when compared to the 570. Was it worth it? Absolutely not, as the stutter is noticeable and if you're like me, it's irritating.


However, to answer your original question... You need the following to complete a SLi or CrossfireX configuration.

Two cards of the same model (I believe AMD cards can be the same family i.e. 7950 and 7970).
Motherboard that supports SLi/CrossfireX
Power Supply that can handle the cards/system.
SLi or CrossfireX bridge

If you're debating on the 660ti, it is a great card, and I've used one personally. Only thing I'd suggest; if you can swing the extra for a 670; it is worth it when it comes to AA and high resolution. The extra memory bandwidth makes the 670 shine over the 660ti. Either way, the 660ti is a decent card.

OK thanks for the reply! So a few more questions if you don't mind...
Yes I know exactly what you mean with that microstutter... I have a gaming laptop that runs a single GT 520M 512MB card (NOT A GTX, literally at GT520M) and I want to get rid of that stutter completely.
So exactly what do you look for in a graphics card's specs? I go on TigerDirect and the only thing I can see is core clock & memory bandwidth & memory interface & stream processors. What exactly is the spec that describes the speed?
So what do you recommend? Buying the GTX 660 Ti, or the GTX 670, or is it worth sacrificing the cash and going with the GTX 680? It's lots more expensive, but I do want a card that will do the job properly.
Also, is a mid-tower case good enough? If I wanted to run dual GTX 670s in SLi say... would a mid-tower be too small?
hey and would you know how much power would be required to run dual GTX 670s? I see they average 450W power needed. Would I literally need 900W+ just to run an SLI configuration? The biggest supply I've seen on the market is the 1200W.
Thanks
Sam

 

[cookybiscuit]

Ignore all the crap about stream processors and clock speeds etc. Any card of the same type will perform about the same, just don't compare specs between two different cards.

Microstutter is different to what you were experiancing. On that card you were probably just getting poor framerates, with a powerful SLI setup you can get framerates through the roof but the game still isn't smooth because theres a latency in the frame delivery.

A 670 doesn't pull anything like 450w, thats total system power consumption. For SLI 670's you'd need about a 650w, but this doesn't mean go out and buy a $10 700w PSU, because it will explode.