subcircuits and speed

Hi All,

I am fairly new to gnucap and spice and I have a question regarding the 
use of subcircuits and the solution times when using them.
I have a circuit network with about 500 or so sets of either; R and L, 
R, L and C, or R, L, C and I,  elements in series. If I perform an AC 
analysis when using this circuit it takes only about 3 seconds to run 
(which is great:-) ).

However, if the same circuit is written in terms of a number of 
subcircuits (essentially RL subcircuits, RLC subcircuits and RLCI 
subcircuits, with roughly 500 or so subcircuit elements in total) and I 
performs the same AC analysis again, it now takes roughly 1500 seconds 
to run. (i.e. the same analysis with the same underlying circuit when 
using subcircuits is roughly 500 times slower than the one done without 
using them).
Should I be specifying an option somewhere to speed this up? and/or can 
anyone give me any tips as to what I might try to improve the 
performance when using subcircuits? (subcircuits are quite neat so I 
would like to keep using them if I can).

Kind Regards and thanks in advance,

Paul