I hadn't played this game for ages when I decided to play it again. The amount of memory stored in the cartridge is a clossal amount due to the large card pool, but duels still seem to be much faster in WCT2006 than in more recent games such as WC2011. Kinda surprising I think. I thought that the speed of duels would improve in later games, not get worse.
I haven't played the recent games but I assume they are like Nightmare Troubadour, which was pretty slow. I like the GBA Yu-Gi-Oh! games because you can speed the duels up (besides this game). I think the speed in the newer games have something to do with the DS or the amount of cards they hold.
Besides being asked if you want to activate a trap card a billion times, I'd say EDS is the fastest for GBA, but this still is the best YGO for GBA and the slower speed matched with the amount of content is understandable.
\_O__/ HEY!! Dallas Mavericks - Your 2011 NBA Champs (YOU SAD, LECRAB?)