For the hardcore gamer dose sli really matter that much if you have a gtx 580 oc? If soo 8 by 8 is that enough or should you only do it if you got a board with 16 by 16? Is there any where that talks about this?
Sli really depends on which cards you want to sli.You don't normally see people sli'ing a 580 because it is power enough as a single card.But sli'ing it would increase performance,if anyone has enough money to sli a 580 then they will usually have a mobo with multiple x16 lanes.
Most mobos run x8/x8 or even x4/x4.Usually it will be the high end mobos that will run x16/x16.But x8/x8 is still considered good.
If you are building a rig that would use SLI from the start, you probably have the budget to get an X58 board that supports x16/x16 SLI. If you just want to have SLI as a possible upgrade path for the future, X8/x8 is probably more than enough. I haven't seen recent benchmarks, but the performance difference between x8 and x16 for SLI used to be 5% at most (which doesn't warrant spending 100$+ on higher-end platform IMO).
There are plenty of boards supporting x8/x8, check for P55 boards. P67 is for the upcoming Sandy Bridge CPU which uses a different socket (LGA1155), most website probably don't even sell those yet.
If i go intel Its either core i7-950 or corei7-2600k Only thing i dont like about the sandy is the 8/8 lanes but will see what asus brings out.
I found a rather recent article comparing x8/x8 to x16/x16 in SLI for you here. The verdict: no performance difference at all unless you go at a resolution above 2560x1600 and even then the difference is ~6% for three 1920x1200 display (5760x1200 total ).
I would also like to point-out that for gaming, getting a CPU that is "upper mid-range" instead of "lower high-end" is often an easy way to save $$$ that can be invested elsewhere in the build (or kept in the bank for future upgrades) without any noticeable gaming performance.