zbrush unwrapping crash

Hello guys , i’m using UV MASTER but always my zbrush just stop responding, my character has 116k of poly and 3 polygroups but always it stop responding.
my config

i3 2100
9800 gt 1gb ddr3 256 bit
4gb ram
500 hd



You can try out:

Geometry --> Check Mesh / Fix Mesh or try

Modify Topology --> Optimize Points

then try again unwrapping