There is no doubt that the main stream i7 Sandy Bridge can easily keep up with the older generation performance chips, i7-9xx.
But expansion capabilities on the Sandy Bridge platform are limited. If you need a raid controller, your video card will downscale to 50% of it's performance, if you need an AJA, BM or Matrox card, you are out of luck. If you need both, forget it.
If you can wait a couple of months, the new Sandy Bridge E is the one to wait for, together with the X79 platform. 40 PCIe-3.0 lanes versus 20 PCI-e-2.0 lanes, quad channel memory versus dual channel, hexa or even octa cores instead of quad cores, 15-20 MB L3 cache versus 8 MB L3, etc.
now behave... you can have both.. but again who needs an 8 drive raid array..
to the OP all the answers you need.. X58 = waste of cash unless doing lots of animation.
Core i7-990X Extreme Edition vs. Core i7-2600K. (page 1 to 13)
What it all means is that the LGA 1366 flagship i7-990X does perform slightly faster in PR (Premiere Pro) CS5.x than the LGA 1155 flagship i7-2600K - but nowhere near three times faster. What's "extreme" about the i7-990X is the price: It costs more than three times higher than the i7-2600K.
And as I have noticed with the higher-scoring quad-core i7-9xx systems in the PPBM5 list, they all use expensive, high-end motherboards that more than offset the cost advantage of the i7-9xx quad-core CPU over its i7-2600K competitor: The typical LGA 1155 motherboard in the higher-scoring i7-2600K systems costs about $180 to $190 while the motherboards in the higher-rated i7-9xx systems almost always cost well over $300. None of the quad-core i7-9xx systems based on lower-end LGA 1366 mobos (priced at less than $250 for the motherboard) ranked higher than about 43rd out of the well over 400 systems on the PPBM5 results list.
Thank all of you for your answers to my OP.