[14.04 64Bit]-Mozilla Thunderbird High Memory Usage?

[Jesse Palser]

Hi,

Running Kubuntu 14.04 LTS 64Bit fully updated ("The Greatest OS In The 
History Of Computers").
I'm on a slow thin client with Intel Celeron Dual-Core CPU and only 4GB 
DDR3 RAM.
I would like to run a Genuine copy of Microsoft Windows 8.1 Pro 32Bit in 
VMWare Player.
My problem is Mozilla Thunderbird email client takes much RAM (~260MB ?).
The email client has just 4 email accounts and all are configured for IMAP.

Is ~260MB RAM usage normal for Mozilla Thunderbird email client?
I would like to dedicate 1.5GB to the VMWare Player Win 8.1 Virtual Machine,
but I am concerned that there won't be enough RAM left for VM with all 
my native apps running.

~260MB seems rather excessive RAM amount for a simple email client?
Any help would be appreciated, thanks!

Jesse