[New Build] Looking for upgrades for a Gamming Rig

[Renakh]

Hey Guys,

I’m looking to upgrade a few components of my current gaming rig to run new and future games with high graphics for a while. I’m currently looking at replacing the motherboard, CPU and video cards although I’m not partial to anything as long as I stay in budget. I’ve listed my current rig parts below and would like some suggestions on what would be the best upgrades within a $1500 - $1800 budget.

(My current board refuses to recognize my SLI half the time and after weeks of help with tech support not being able to pinpoint the issue I’ve decided to just upgrade.)

Current Rig:
SSD: Crucial RealSSD C300 CTFDDAC128MAG-1G1CCA 2.5" 128GB SATA III
Motherboard: ASUS P7P55D-E Pro LGA 1156
CPU: Intel Core i5-760 Lynnfield 2.8GHz LGA 1156
RAM:16 GB - G.SKILL Ripjaws Series 4GB 240-Pin DDR3 SDRAM DDR3 1600 - Model F3-12800CL9S-4GBRL
PSU: Antec TPQ-1200 1200W
Video Cards: 2x ASUS ENGTX470/2DI/1280MD5 GeForce GTX 470 (Fermi) 1280MB 320-bit GDDR5
Network Card: VisionTek Bigfoot Killer 2100 Gaming Network Card
Audio Card: Creative PCI Express Sound Blaster X-Fi Titanium Fatal1ty

 

[Renakh]

Currently I'm looking at the following:

Motherboard: ASUS P8Z77 WS LGA 115
or
Motherboard: GIGABYTE G1.Sniper 3 LGA 1155
CPU: Intel Core i5-3570K Ivy Bridge 3.4GHz
Video Cards: 2x XFX Double D FX797GTDFC Radeon HD 7970 GHz Edition 3GB

I do have some questions...

is it worth getting a x16 x16 vs x8 x8?

is the i7 worth getting?