You should practice COMBINING scales... being able to weave in between patterns..

it doesn't matter how fast you can burn up and down the guitar, but rather how WELL you know the scale patterns and how they're used together..

can you quickly transition from mixolydian to phrygian without even thinking? can you do it from the 4th string? can you do it with your eyes closed?

can you start a phrase in dorian and end it in locrian?

that's what you should practice. speed doesn't matter... :)