Success
!
I first received a 2nd 6-pin cable in the Mail (I had ordered this prior to ordering the 6-to-8 cable, before I knew I had mistakenly ordered an overclocked vid card). Since I had to wait another 3 weeks for the 6-to-8 pin adapter, I got a little impatient and I researched more ... found this ...
http://www.tomshardware.com/reviews/power-supply-specifications-atx-reference,3061-12.html ... and then realized the extra 2 pins on the 8-pin card-side are both GROUNDs ... meaning no power "required". They only signal the card to activate OVERCLOCKING and DRAW EXTRA POWER. Also, the article explained that there is normally only ONE safe way to plug the 6-pin PCI-e cable into the card, and "unless you force it", it will normally only work one way (with the snap-on holder facing upward, you would put the 6-pin into the 8-pin toward the RIGHT). So, I figured I'm safe to use ONLY 6-pin PCI-e cables for the time being (of course with this configuration you're bypassing the over-clocking, which is not taking full power advantage of the card). When I get the 6-to-8 I will probably give that one a go too

, but can happily confirm that I've been working with the card for a half a day with no problems so far (ok, let's see after some weeks). Prior to HEAVY, LONGER Rendering activities I'm still gonna do some more tests, and monitor temperatures. -- regards, J.