I'm running vagrant on OSX, Ubuntu, and Windows 7 and using vim and Netbeans as IDEs on the host machine. The VM is running CentOS 6.3 and Apache 2.2. The docroot is set to
I had this problem this morning. Set EnableSendfile to off in your httpd.conf.
If you look at your httpd.conf it says "turn this off if you serve from NFS-mounted filesystems." In http://httpd.apache.org/docs/2.2/mod/core.html#enablesendfile it explains that "By default, when the handling of a request requires no access to the data within a file -- for example, when delivering a static file -- Apache uses sendfile to deliver the file contents without ever reading the file if the OS supports it."
Since your windows host has an ntfs file system, the linux guest doesn't properly cache the file with sendfile and so apache needs to send the file itself. This may cause a marginal slowdown when requesting files from apache, but it should be negligible.