Files on the computer in high speed, while normal on the Recorder

You can format the device, maybe if you delete files on the device from the computer , you cause inconsistence between them, i suggest to erase files using the buttons on the device. about the high speed check the codecs in your computer,
I can’t play a file that Windows Media Player supports. What should I do?Most likely, a required codec isn't installed on your computer. Typically, Windows Media Player automatically downloads any required codecs from the Internet and installs them. However, this may not happen for the following reasons:
• The necessary codec (typically, a non-Microsoft codec) isn't available on the codec server.
• You have an older version of the Player and your automatic codec-download option isn't enabled.
• The Internet security settings for your browser are set too high.
• You're not connected to the Internet.
If you have an older version of the Player (prior to Windows Media Player 9 Series), you can check your codec download setting by doing the following:
1.
In Windows Media Player, on the Tools menu, click Options, and then click the Player tab.
2.
In the Auto upgrade area, make sure Enable automatic codec download is checked, and specify how often you want the Player to check for updates.
You can change your Internet security settings (if you are logged on as an administrator or a member of the Administrators group) by doing the following:
1.
In Control Panel, open Internet Options.
2.
Click the Security tab, and then click Internet.
3.
In the Security level for this zone area, click Default Level.
If you can’t play the file after completing this procedure, restart your computer, and then try to play the file again.
If you still can’t play the file, try to play another file with the same file name extension. If you can play this file, then there is a problem with the file that you want to play. For more troubleshooting information, see the Windows Media Player Multimedia File Formats Web