I found gmx pdb2gmx is very slow when I create .top of big polymer [with 37w atoms]

GROMACS version: all
GROMACS modification: No

Currently, I want to create a top file of polymer via gmx pdb2gmx combined with .rtp file.
However, I found the process is very slow if the polymer is big, maybe cost hours and still can not finish, terminal also shows:
Total mass 2630070.831 a.m.u.
Total charge -0.000 e
Writing topology

I upload a test file download, you can reproduced the behavior by command:
gmx pdb2gmx -f conf.gro
then choose:

Is there a method to improve speed?

Yujie Liu