Thank you for the quick response! I rebuilt the index but performance appears unaffected.
I believe I have narrowed down when the sluggishness happens:
If Alfred is used when on the Integrated Graphics Card (Intel HD Graphics 4000), there is a slight delay as letters are typed.
If Alfred is used when on the Discrete Graphics Card (NVidia GeForce GT 650M), responsiveness returns to normal.
Not sure if there is anything that can be done about this, but at the very least, it has now been documented.
Thank you for your help so far, and for making such a fantastic product. If this turns out to be the only issue I encounter in years of using Alfred, it is still a far better and more well-designed program than most.