Not sure about the amount of memory making a difference. But if you bought it from ebay there have been a huge number of Sony Fakes going abouts. I read and article i found on digg.com. Seems that some clever people have managed to get a 32MB drive to appear as a 8GB flash drive. Some how tricking windows drive management. Just a little FYI.
I have a 64Mb Memory Stick Duo which I use in an mp3 player. With this stick the mp3 player's battery lasts around 15 hours of mps listening. I recently bought a 2Gb Memory Stick Duo - using this card the mp3's battery life is only around 7 hours.
Does anyone know if larger capacity memory cards of the same brand and type have a higher power consumption than smaller capacity cards? If not then it looks like the 2Gb card I bought is a fake.