Hello tterien,
I would check to make sure you have latest software (which you can check at Lowrance's website
http://www.lowrance.com). Remember to back up your waypoints and other data before you update if it is necessary.
Also consider that your friend's machine may be operating a little faster because his is operating off of the hard drive's charts as apposed to your machine which has to operate off of the SD card in the slot. As a rule hard drives read a little faster than the SD card, so perhaps that it is why it seems like yours is operating a bit slower than his. Let me know if you have any questions about this. Thanks, and have a great day,