Massive slowdown when "No Sound" is selected

[GoogleCodeExporter]

1) What version of the product are you using? On what operating system?

Latest version as of February 17th 2015
Windows 8.1 x64

2) What steps will reproduce the problem?
1. Go to Config > Audio > SPU2 Plugin Settings
2. Set "Module" to "0 - No Sound (Emulate SPU2 only)" while game is running

3) What is the expected output?  What do you experience instead?
I expected little/no change in FPS or even a speedup, but instead I experienced 
a drop from 50FPS (full speed) all the way down to 16FPS with No Sound enabled.

4) Please provide any additional information below.
GS utilization dropped down from ~10% to 0% and EE utilization skyrocketed from 
~75% to 100%

Original issue reported on code.google.com by [email protected] on 17 Feb 2015 at 3:23