There are two things that normally help performance issues on PS3:
1.Rebuild PS3 database Sometimes it also helps to rebuild your PS3's database as described here: http://www.ps3blog.net/2011/01/28/tips-and-tricks-ps3-rebuild-database-faq-recovery-menu/
2. Turn off the PS3 Media Server which is a resource hog taking up system resources that DAI really needs to work. The Media Server Connection allows other devices to connect to your PLAYSTATION 3. Often, the Media Server Connection is known to cause issues when players try to connect to the Internet for online game play.
- Access your Xross Media Bar menu
- Navigate to Settings
- Select Network Settings
- Select Media Server Connection and choose the Disable option.