The other day I randomly decided that I should figure out how fast I can alternate pick on one string without worrying about my fretting hand. Literally just picking one note. So I decided to play 16th notes and started dialing up my metronome. The results kind of shocked me, as I couldn't play as fast as I thought!
I got up to about 185 bpm picking 16th notes, and that was really hard. I'd say comfortably I could pick 16th notes at 175 bpm. And at that speed you can't even really count 4 pick strokes, you kinda just need to know what groups of 4 sound like. It was almost more difficult for my mind to keep up than my hand.
When it comes to actually playing chromatics, I got up to 145 bpm playing 16th notes.
So if you haven't found out your max in either of these exercises, go for it. It's a good exercise anyway.