Smooth text scrolling was already a subject in QC, I remember one guy that found a workaround using Java code to smooth scroll.
Made a simple composition, not smooth for me neither, actually it seems the text is smoother with the original window size, gets worse when I resized it (not even sure).
Even turned off multisampling.
This happens for big texts but also with smaller font sizes.
My HD 3000 is old but I would hope recent Macs would handle this.
It runs at 59/60 FPS though and the cpu load is low too.
Tested in Vuo 1.2.6
Does this happen for all Macs ? Or would @grahamis his GPU fallback some graphics to the CPU too like the HD 3000 bug and be the cause for non smooth text scrolling ?