Yeah, I'm also running a 63mA dc-dc converter and it barely gets warm, but it's more about how sharply it can switch the Fets; I'd imagine the 2A drivers switch the Fets a whole lot more quickly than my 0.125A drivers, given that the gates can take a couple of amps to switch at their full speed.. Another downside of my drivers is they keep dying after a few fights, and I have no idea why... They're the same used in TZ85s so I'll have to properly scrutinize their circuit layout to make good of the current batch of boards; I've already had offers for the lot of them and could use the money :P