It's not too much for my MacBook Pro - I resample all my music to 2xDSD, in addition to adding several other DSP options (Parametric Equalizer, Headphone, etc.).
Mine (Late 2011 2.5 GHz i7, 16 GB RAM) runs at about 10-15% utilization during playback.
My benchmark results, FWIW.
=== Running Benchmarks (please do not interrupt) ===
Running 'Math' benchmark...
Single-threaded integer math... 4.028 seconds
Single-threaded floating point math... 2.662 seconds
Multi-threaded integer math... 1.132 seconds
Multi-threaded mixed math... 0.785 seconds
Score: 2207
Running 'Image' benchmark...
Image creation / destruction... 1.787 seconds
Flood filling... 0.502 seconds
Direct copying... 1.012 seconds
Small renders... 1.522 seconds
Bilinear rendering... 1.413 seconds
Bicubic rendering... 0.647 seconds
Score: 3196
Running 'Database' benchmark...
Create database... 0.468 seconds
Populate database... 1.819 seconds
Save database... 0.189 seconds
Reload database... 0.065 seconds
Search database... 1.313 seconds
Sort database... 1.223 seconds
Group database... 1.020 seconds
Score: 3526
JRMark (version 19.0.144): 2976