A
does dual graphic cards doubles memory bandwidth or SLIing(even CFinig) does the same
dual graphics
What else do you want with SLI & CROSSFIRE? 
@ Abhilash S - in theory it doubles the bandwidth but in realilty they offers 20-50% performance gain & it depends on a lot of things like optimized drivers & optimized apps/game engines which can take the advantage of multi gpu.
A
Then what r all doubled & wat not?please tell me
Theoretically everything will be doubled...your video memory, bandwidth and even theoreticaly your performance should double but the problem is that it is very hard to code a game engine for multiple graphics cards so you will never get 100% increase in gaming performance...you will get anywhere between 40 to 60 maybe 70% increase
M
sli and crossfire are a waste of money. u lose half of the performance of a very good card. on the other hand, they are redudant, one dies u are left with the other. i suggest getting a single more powerful graphics card for the price u spend on two cards, the motherboard, cooling and the power supply.
They are not actually a waste of money. Some people wants only the best thing out there. So it's a great thing for them. Now think about running 3x GTX 295 in 3 way SLi setup with a core i7 & only a single GTX 295 with a core i7. Will they perform same ?
With a same rig you are getting 50 - 160% ( in case of quad sli ) without the need of changing to a single powerful GPU over time.
So avid gamers always prefer multi GPU setup with CF or SLi.
SO, It's not the SLi technology that should be blamed but it's the game engines which is not optimized for SLI. Same is the case with CF.
Also more games are releasing with SLI support like more games are now optimizing them for Quad core & dual core cpus.
With a same rig you are getting 50 - 160% ( in case of quad sli ) without the need of changing to a single powerful GPU over time.
So avid gamers always prefer multi GPU setup with CF or SLi.
SO, It's not the SLi technology that should be blamed but it's the game engines which is not optimized for SLI. Same is the case with CF.
Also more games are releasing with SLI support like more games are now optimizing them for Quad core & dual core cpus.
M
at the same time, graphics card get a 40-50% boost over a span of 6 months. u have a triple sli and in a year or two u can get single card that will beat that setup. take SLI 8700GT, a single 8800Gtx can easily beat them out while a GTX 285 can even kick them further. but that is just year diff in release. it is way bettter to buy one this year and add sli next year with next gen card
^you cant sli or cf 2 different generations of cards.....sli/cf is not a waste of money. If you have the money to go for such a setup then you definately should.
But if I've the money I'll get a Sli mobo & put 2 or 3 even 4 fastest gfx cards
when they will be available. Like in case of crysis very few single card can give over 30fps @ very high resolution. But muli gpu solution can perform better than single card in such case.
Even 2 9600Gt performs bettr than a single 8800GT. Now a 8800GT is Rs. 9K.
But 2 9600Gt is only Rs. 11.4K.
In case of 9800GTX+ it's Rs. 11150.
But 2x 9800GT will perform bettr than 9800GTX+ which is only Rs. 14.6K.
Also I've to wait for 6-12 months before changing a gpu. But good new games are releasing every month. What I would do if I want to play them @ high settings for ultimate gaming experience during the time span of releasing a powerful gpu that will perform better than sli or CF.
So it's wise to go for multi gpu setup if you have the money.
N
^^
+1 Well said & it's true.
+1 Well said & it's true.
^^ Thanks mate.