PSU for 2 VGA`s - what exactly ?

[Kent]

Hey guys! Im in trouble and I`ve always watched Linus for information, so today I decided to ask for help .

 

My problems are:
I have 2 vga`s 

EVGA GTX770 SC 2GB and Radeon HD6850 2GB.

1st problem - What PSU do i need to power up both? I`m thinking of an

-XFX ProSeries Core 850W
(ATX 12V V2.31, 80 Plus Bronze, Standard, 2x 6pin PCIe, 2x 6+2pin PCIe, 11x SATA)
or 
- XFX ProSeries Core Edition 750W PSU
(ATX 12V V2.31, 80 Plus Bronze, Standard, 2x 6pin PCIe, 2x 6+2pin PCIe, 8x SATA)

 

2nd : What exactly do I need , do I need molex or sata, I read about them in various places but kinda didn`t understand them (stupid me)
3rd: Will I bottleneck my system If i keep both cards (although I think its a yes)

I bought the gtx as an upgrade. Also here are my other system specs if needed:
CPU: i7 2600 3.4 GHz
MB: Gigabyte Z68X-UD3H-B3
Mem: 16 Gigs
Integrated Graphics: Intel HDG 1000GT1 

Im really looking forward for an anwser. Sorry if I make you guys answer obvious question I just need to make sure im not going to trash my system somehow . Thank you in advance

 

[Thx And Bye]

Do you want to run both cards simultaneously, or just switching between them?

[Kent]

Both at the same time. Or if its possible to use one for Autocad an the other for gaming

[Kyl3]

the 750w will power them but, personally I would go with the 850w just for extra head room.

[Thx And Bye]

The easyest way, known to me, is it doing like this:

-> http://youtu.be/YqkI7bOfRkA?t=4m6s

 

Just "downscale" it to only 2 Cards, which should not be so different.

If you're doing it like this, than you would only need to power 1 card at a time and wouldn't be worrying about the PSU so much, and the 750w schould be no problem at all.

[Kent]

Thank you guys. Ill do it in a jiffy