According to the Plextor site home page > burning > support > compatibility > Mobos w/716SA - some owners have reported compatiblity with the A8N-SLI but not tested in-house. You might also want to browse/search the Plextor section on the
http://www.cdfreaks.com web site for the experiences of others with your mobo. May save you some experimentation...
Make sure you have the latest stable BIOS for your mobo. Others have found better results in one SATA mode or the other (IDE or RAID) which should be selectable in the BIOS. One would think that IDE mode would work best with optical drives as you really can't RAID them, but "it ain't necessarily so".
Even though I really like, constantly recommend and have owned Plextor drives for at least the last 6 or 7 years, and their software packages offer more technical stuff and fine control than most others, you can get nearly as good every-day burning performance for a lot less $$s with other brands (e.g. Benq 1640 which is practically the same drive as the PX-740A).
BTW, those IDE to SATA adapter/converter cards really do work, but do add one more variable into the equation.
And be aware that you can often find a better bottom-line price on Plextor drives from other top-20 online resellers than from Newegg. Try Froogle, Pricegrabber, etc.
.bh.