Slow in Commit via UberSVN

Hi
I use ubersvn for manage own source codes but in last days commit on it is very slow (4 Minutes) , ofcourse slow rate in SVN can be refused commit it .
Some times it can commit (slow) but in return response it very slow .


My repositories size is 20GB and i Define 200 Repositories with 100 Users.

Please help , It's very critical for me .


Thanks .