No prob!
Did any of this work out... or problem still perists?
EDIT
Oh shit... actually read your full initial comment.
Yes, if the entire game... or Steam... is running from an external HDD... including the shaders and such?
Shaders generally are used many times, every frame.
Having those on an internal SSD could make a difference, and possibly be part of the problem you've shown, depending on your total hardware setup.
Generally speaking, more graphically complex 3D games that make substantial usenof shaders should be run from an internal SSD.
You can do HDD for 2D or less complex 3D games and its usually fine, but if fancy pants shaders are involved in many more modern games, use an SSD if you can.

