safe to convert SATA power cables for second PCIe power cable, using adapter ? [with specifics]

[delicious-unix]

so here is my power supply:

and a little more info: http://www.bequiet.com/en/powersupply/326

i am looking to connect a HD 6850/6870 to this computer, which requires two PCIe power cables.
according to this, the maximum power draw of the 6870 is 150W
http://www.bit-tech.net/hardware/graphics/2010/10/22/ati-radeon-hd-6870-review/2

however, the power supply has only one PCIe connector. but i do have tonnes of spare SATA power cables. can i buy an adapter that will connect the SATA cables to the power supply, safely ?

the computer uses an i5 2400S and the bare minimal of other components. i have read that a two way splitter on a PCIe power cable is a bad idea

i have also contacted the manufacturer of the power supply with the same question

 

[Vic 40]

Why that old gpu? Why not a gtx 660 or something like the hd 7850?

I wouldn't convert sata cables since they probably are fed of the same rail as the cpu.That psu has two +12V rails and one primarely for the gpu/pcie afaik.

 

[delicious-unix]

i just want to play wii games at highest quality, i'm not a big gamer. these graphics card don't cost much. but i'll check out your suggestions.

i have just read here that a PCIe port + a PCIe power supply actually provides 150W together ? is this true ?
http://www.tomshardware.co.uk/power-supply-specifications-atx-reference,review-32338-12.html

what if i convert the molex ? it has one molex

 

[Dark Lord of Tech]

Bad idea , to do that with a poor quality PSU.

 

[delicious-unix]

i thought 'be quiet' was good quality 😱 they had the best component wattage calculator, a solid website, the brand name that is germany (although VW dented that). i don't know how to choose a power supply brand based on actual electronics, but it wasn't cheap compared to other brands

anyway i have discovered the 6850 actually only needs one PCIe power supply ! so i will probably buy that, or a 6790, or 7770, both are a bit less powerful, but just below the threshold of needing two PCIe power cables
i was, much earlier, also looking at the 5850 and 5870, but they are less power efficient, and both need two PCIe cables.

 

[Vic 40]

The Be quiet isn't that bad,but it is the right decision to go with a gpu that only needs one pcie power cable.