It's currently up to 308Mb of RAM.
Is this normal behaviour? Should I be concerned?
It's currently up to 308Mb of RAM.
Is this normal behaviour? Should I be concerned?
There appears to be something inherently wrong with the Gmail Notifier as it is using much too much memory and is also eating your CPU cycles. Google last updated it back in 2006, and it might not be compatible with the latest versions of Firefox anymore.
I would suggest using an integrated Firefox add-on instead, such as Webmail Notifier.
That looks like some kind of memory leak, which is a problem with the application itself. I would use an integrated addon like @Paul Lammertsma said.