Computer timing shows a 25.6% speed increase over the factory ROM.
Just remember this is only because the program uses a lot of multiplication.

0 TIMER=0:POKE65497,0
10 PMODE4,1:PCLS0:SCREEN1,1
20 DR=3.1415/180:DS=SIN(15*DR):DC=COS(15*DR)
30 FORR=5TO330STEP10
40 FORT=0TO360STEP10
50 X=R*COS(T*DR)*.25
60 Y=R*SIN(R*DR)*.25
70 Z=R*SIN(T*DR)*.25
80 XP=X+(DC*Z)
90 YP=Y+(DS*Z)
92 XP=128+XP
95 YP=80-YP
100 PSET(XP,YP,1)
110 NEXT:NEXT
115 T=TIMER/60
120 A$=INKEY$:IFA$=""THEN120
130 PRINT"TIME:",T