And what exactly? You have not told us anything here. No comp settings, no render settings, no system info. not what effects may actually be used.
Comp settings are HDTV 1080, 29.97, Rendering in H.264 in AME with match source high bit rate, system Intel i7-3770K @ 3.50 Ghz, 64-bit, Geforce GTX 660. Effects are minimal. Using QuickDraw AEscript and some sharpen, and those are the extents of effects. No dynamic links with Premiere Pro.
Maybe I should have added that none of those have been different than previous renderings. The only time I've had this anomaly is after updating to CC 2014 from CC. The slowdown isn't congruent with effects used.
You should still have CC (version 12 of AE, well, hopefully version 188.8.131.52) on your system. Does it render that same composition at the normal speed?
Thanks for reply. Having seen no apparent issue with the crossover to 2014, I uninstalled CC. That of course wasn't the smartest thing. However, I've had a few days now of success -- I closed out of absolutely every other program after beginning the encoding in AME, and also closed-down After Effects. Since then, it's been rendering without too much of a hitch. I guess there's a memory issue happening somewhere. Perhaps 2014 is more resource-heavy? Anyway, so far things are going ok. I also "saved as" a CC version of the file, which might also be the reason for the current success.
There have been a few issues with memory in AE CC 2014. For example, holding CMD and scrubbing to preview audio (ctrl on Windows), results in a memory leak.
I would suggest, if you have problems in the future, that you download CC version 12 again (make sure you update it to 184.108.40.206). That way you can keep working without trouble until the next bug fix for version 13 comes out.