SLI features an intelligent communication protocol embedded in the GPU, a high-speed digital interface to facilitate data flow between the two graphics cards, and a complete software suite providing dynamic load balancing, advanced rendering, and compositing to ensure maximum compatibility and performance in today’s latest games. And a gtx540m 256 bit 2gb dedicated and total of 4 gb memory gpu is not a strong card yes kryil... Do you want a basic definition for SLI?