Email size limit?

Is there a size limit on Emails?
I have been getting support from Logitech Harmony Remote people and the last time I tryed to add to my Email from them eM Client as going unresponsive but only using 17% of the CPU AMP Phenom II X6 1100 3.3GHz 8Gig ram Win 7 Home Premium.

EM Client has no restriction over the size limit of the e-mail. You need to check with your mail provider, or ISP.

I had no problem getting the Email.
Its was that when I was trying to add something like 50 lines in reply that it kept locking up, CPU use was not much and I have nothing else running at that time.
I also had just finish a virus, malware and registry check.
I had to cut and paste what I was adding to the Email just to stop it locking up.