question

[gman123]

what does SLI ready PSU and Memory mean? and do you have to have it if you do SLI graphics.

 

[Gravemind123]

You do not have to have it, it is marketing BS at its finest. Power supplies can be examined by nVidia(I'm pretty sure you have to pay for nVidia to do this) and be deemed "SLI ready". This means the PSU is rated to handle SLI by nVidia. There are some great PSUs without this rating and some crap PSUs with it.

SLI Memory means the memory supports EPP, which in 650i and 680i motherboard allows the manufacturer to add higher frequency and better timings values into the ram that don't comply to JEDEC standards, and that will only be found in motherboards supporting EPP. You can go set the timings and frequency of your ram to anything you want in the BIOS anyway, so this is just a convienence, and also can be used as an excuse to charge you more money.

The only things required for SLI are 2 identical nVidia graphics cards(memory size and manufacturer can differ, but core must be the same) and a motherboard based on an nVidia SLI chipset.