what's the difference between sli and crossfire and the benefits ?

[2013]

Hi I know this maybe a silly question to some,
I wanted to know the what's the difference between sli and crossfire and the benefits ?

I know nvidia sli only works with 2 of the same cards and the benefit is about 20%

could someone give me some more information

 

[2013]

Does crossfire support different cards or like Nvidia you need to have matching cards ?

 

[2013]

My problem is, ive never looked into sli or crossfire and ive mostly used Nvidia

 

[2013]

Thanks, forgetting price and card is there any real difference in the 2, other then the software gimmicks ?

 

[2013]

Thanks guys. at least some people reply with some information.

 

[2013]

if it came down to price does it matter if its amd or nvidia ?
do any of the little tweaks justify the cost, example 280x - gtx 770