Ok, here are the test results with everything else being the same but with no anticipative FX. Due to big performance difference I had to up the sample buffer from 32 to 1024 to keep clean playback though. Lower buffers produced progressively worse dropouts and glitches.
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Intel i7 4770k @ 3.5GHz
Windows 10 64-bit
Reaper x64 versions
ASIO Hammerfall DSP, 1024 samples, 44.1kHz
Tracks: 84 2-ch. audio tracks, all files 44.1kHz stereo WAV
Plugins: 252 instances (ReaEQ, ReaComp and ReaFir on every track)
No 3rd party plugins
Other notes: All tracks straight to master, no folders, no sub-busses.
All measurements taken 40 seconds into project.
VS2005 & ICC x64 no anticipative FX
VS Express 2013 x64 no anticipative FX
Later maybe 32-bit versions...but the performance differences seem about as small as previously?