I am using AVR Studio (4.14b589) to debug projects over JTAG. I've found it takes a very long time -- 17 seconds -- to open the disassembly window on my fast Vista x64 machine, while the same project on a (slower) 32-bit XP machine takes only 4 seconds. I have used both JTAGICE MkII and AVR Dragon, and debugged both ATmega16 and '324P projects with the same results. Further operations in the disassembly window (i.e., program jumps to new code) also take a long time.
Have other folks experienced this issue? Are there any settings I can change to improve this? I'm guessing this is a data transfer issue over the USB port.