The key to write speed for SSD/USB thumb drives is pretty much the same as hard drives. Stripe them for better performance. The difference is that SSD/thumb drives can achieve striping internally with multiple chips. The more individual flash chips in the device, the more it can distribute and not have to wait as long for the previous write call.

Odds are that older 2GB thumb drive has a few NAND chips in it, whereas modern ones may only have a single chip.