I transferred a 300mb of file to my 8Gb SDHC in my bold using the usb cable from my laptop in 10 seconds. Could not have done that with my Curve.
That is fast. So I'm guessing the Bold has USB 2.0 rather than USB 1.1.
It's amazing fast. I was gonna do something else and when I turned around, it was half way done. When I went back to my computer to unplug the cable, it was done! I didn't even go more than 2 feet away from the computer. WOW!
Blackberry Bold by AT&T - Current
Blackberry Curve 8310 Gray - Spare
Blackberry 8800 - Past
Yes your talking 480 Mb/s (thats Megabits not MegaBytes divide the number by 8 to get Bytes) compared to 12 Mb/s. You better believe its faster. Problem is that you are always limited by your bus speed so if your bus speed is only 333 Mb/p then you will never see 480 Mb/s so as JW021979 pointed out it is still faster to use a USB reader to write to it. I have no idea what the bus speed is on the Bold.
I too found that the memory card is noticeably faster than going direct to the Bold. I searched all of my options at both BestBuy and CircutCity and found a 50 in 1 card reader made by Digital Concepts. It doesn't read MicroSD directly however my MicroSD card ($17 for 8GB) came with a SD adapter. I leave the SD adapter in the reader which makes it easier to insert and remove the MicroSD. This reader also works for my camera's XD card, PSP Memory Stick Duo and other misc cards I have laying around the house. The reader is the size of a match book and cost less than $25.