Browsers and large HTML tables

What is wrong with browsers displaying large HTML tables? Well, I had to look at a "CISCO global price list" (looking for the price of their latest alleged gpl violation). Of course that list is only available as .xls, so I used xlshtml to convert it to HTML. THe result is a 12MB HTML document.

Opening that HTML in w3m took quite some time on my dual Opteron 246, and I was wondering why it took so long (it indicated it was opening the file from the local hard drive at 9.6MB/s, though). Looking at top, I hardly believed my eyes. The total virtual size grew up to 760MB(!)

I then re-tried with Mozilla, and it did equally bad with 815MB. However, I would have expected something like this from Mozilla, being a monstrous GUI program... but w3m? I'm puzzled.