The old wyrms will NOT eat gold. That is part of how you can tell they are old. Gold eating was a recent addition to them. All white wyrms tamed now eat gold.
The really old ones sound like a dragon, not a white wyrm. Dragon roar and all. They don't actually breathe ice. It does have the full hued breathing animation, though. I have a friend with one of the first White Wyrms. I like it's roar.