The time required to compute… 
is roughly proportional to 


an overall factor analysis 


the correlation matrix 


PRIORS=SMC or ASMC 


PRIORS=MAX 


eigenvalues 


final eigenvectors 


generalized CrawfordFerguson 


family of rotations, 

PROMAX, or HK 

ROTATE=PROCRUSTES 

Each iteration in the PRINIT or ALPHA method requires computation of eigenvalues and f eigenvectors.
Each iteration in the ML or ULS method requires computation of eigenvalues and eigenvectors.
The amount of time that PROC FACTOR takes is roughly proportional to the cube of the number of variables. Factoring 100 variables, therefore, takes about 1000 times as long as factoring 10 variables. Iterative methods (PRINIT, ALPHA, ULS, ML) can also take 100 times as long as noniterative methods (PRINCIPAL, IMAGE, HARRIS).