There are no "conventions" connecting the note values and the tempo. Those are separate categories. Any given tempo is measured by the number of beats per minute (at least since the Beethoven days, at which time the metronome was invented), the note value for the beat given in the time signature (i.e. */4 meaning the beat is a quarter-note, */2 the beat is a half-note, etc.). The note values, on the other hand, are measurement of their relative lengths, compared to each other: a half-note lasts half as much as a whole-note, a quarter-note half as much as a half-note, etc., in any given tempo (sorry if I'm explaining the obvious). There is a plethora of pieces using very small note values (thirty-two notes, sixty-four notes, even smaller) and still being in a generally slow tempo; take a look at some of the slow movements from Beethoven's sonatas for instance. Of course, the small note values themselves may call for some pretty nifty finger-work in some of these movements (e.g. Sonata op.10 No.1 in Cm, Adagio molto), but that doesn’t change the tempo of the piece - keep in mind what I said earlier about the tempo and how it is measured!
