Hello and thank you for your time! I'll make this quick...
Do I even need the Kona LHi for RAM Previews in After Effects? Is it helping with the speed of playback at all? Or is playback on the third "desktop" monitor just as good / just as fast?
12-Core Mac Pro
AJA Kona LHi
3 Displays (2x 20" Cinema Displays, 1 Panasonic LCD)
Hooked up BOTH for 3 desktop monitors (1 x DVI, 2 x Mini Displayport - Dual Link DVI), and for output to the Panasonic through the AJA.
The only advantage the LHi is giving you is broadcast quality output at "nearly" the same playback rate as your computer desktop.
ALL potential acceleration is handled by the Mercury Playback Engine inside CS6 and appropriate graphics card (if present).
So, if you need to monitor image quality on a broadcast monitor, you need a Mercury "Transmit" capable video device (i.e. LHi), but that device is not providing any acceleration over the Mercury Playback "Engine".