Do you have the Rich Text Editor on?(Edit: posted from said G4, btw; only wish this site was a bit more responsive in its browsers...)
If there is a series of text formatting tools inside the reply box then you have it on. Go into your settings here on the forum and turn it off.
It's javascript code that is executing ALL the time and it's that issue that causes the forum to drag.
You can still format text using tags enclosed by brackets. B for Bold, I for italics, U for underline, S for strikethrough and QUOTE for quotes. The end tag is proceeded by a forward slash "/".
Smilies will appear if you use standard texting characters.
Hope that helps.