I have a forum with roughly 3,500 members (average) and it gets between 500,000 and 600,000 pageviews a month.

Yet even with cache enabled the forum alone, despite seeing very few daily postings, takes roughly 30 - 40GB's of bandwidth! This is utterly ridiculous and I simply can't believe how poor it is.

I can't upgrade because v6.1 isn't out of beta yet and despite that it's 'Category Only' interface is likely to be just as poor and I don't relish having to re-design it myself yet another time.

Any suggestions on why this is happening or how I can really kill some of the bandwidth?