New member, first time builder, bottle necking question?

[Rdub69]

I have all my parts otw from newegg this week.
The list consist of:

In-Win Dragon Rider R full case

• • 1 x Crucial M4 CT064M4SSD2 2.5" 64GB SATA III MLC Internal Solid State Drive (SSD)
  • 1 x ASRock Z68 PROFESSIONAL GEN3 LGA 1155 Intel Z68 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard
  • 1 x Standard A133 Black USB Wired Optical 800 dpi Mouse (free add on)
  • 1 x COUGAR SX850 COUGAR-SX850 850W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS SILVER Certified Modular Active PFC Power Supply
  • 1 x ASUS DRW-24B1ST/BLK/B/AS Black SATA 24X DVD Burner - Bulk - OEM
  • 1 x Intel Core i7-2600K Sandy Bridge 3.4GHz (3.8GHz Turbo Boost) LGA 1155 95W Quad-Core Desktop Processor BX80623I72600k
  • 1 x ZALMAN CNPS9500 AT 2 Ball CPU Cooling Fan/Heatsink
  • 1 x G.SKILL Ripjaws X Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL8D-8GBXM

I put a couple weeks into this $1500 build, now my issue is GPU, due to budget I can not decide between 1 x Gtx 580 3gb card by MSI, or 2 x Gtx 560 2gb by palit.

My plans are to be able to do all my graphic design and editing, play the newest games coming out, and take advantage of multiple 120hz monitors, possibly in 3D? With 1080 or higher resolution.

I am not very fluent with graphics cards, so my questions are:

1. Is a 850w silver PSU good enough for a gtx 560 x 2 set up?
2. Is it enough for gtx 580 x 2, if I were to get one now, and one more down the road?
3. Would I be GPU limited by 2 x gtx 560?
4. And lastly do processor cores on gpu work the same as vram? as in sli/crossfire mode you share the gb vram between cards?

 

[NeXuS1]

1. Yes more than enough up to GTX 580's in SLI.
2. Yes
3. I dont think so get 2 X GTX 560 ti's, they own a single GTX 580 and there cheaper
4. No it doesnt if both card are 1GB the VRAM will be 1GB.

 

[Rdub69]

Thanks, I figured I was safe.