I have consistently observed that during the day, running NOF results in significant browsing delays. Then, at night, everything is fine again. I have confirmed that this is a NOF issue by disabling NOF, which results in much faster browsing during the day.
This may indicate a back-end capacity issue with the NOF servers.
Versions:
NOF 2.3.0.19
Windows 7 SP1 (64-bit)
IE 9 (32-bit version)