Graphics card

I recently purchased a new computer to run Premiere Pro... 32GB RAM, 1TB SSD, i7 processor... but, unfortunately, the graphics card is coming up short on horsepower.  I'm trying to find an acceptable SFF graphics card that does not require additional power (6 prong plug... I don't have any extras available inside the desktop).  Does anyone either know of a good graphics card that meets the system requirements of Premiere Pro... or a way to add an additional 6 prong plug? (maybe a splitter)?