Audio rendering slowness

? about audio rendering in 8.8.6. I just stitched a bunch of scenes (stereo top/bottom, 6k) but had forgotten to turn on audio rendering. Whoops. Was getting 2.7fps without audio. But when I turned on audio rendering, speed dropped down to 0.12fps. I must be doing something wrong because audio can't be reducing speed by 2 orders of magnitude. Instead of rendering the audio (option #1 in the render dialog) should I be using "audio from file" for this? I've got 20 sequences queued up, and if I use "audio from file" will it find the audio that's in the first camera's movie file in each sequence? Confused, thanks for the help... (weird).