since i just purchased a new dru-500a a few weeks ago and was not aware that the dru-500ax was even coming out i decided to simply contact sony and ask what the difference is between the 2 drives. here is a copy of the exact transcript (minus my full name and telephone number)... :
This is an automated email sent from the SONY NetAgent
Server. The following information is a log of your session. Please
save the log for your records.
Session ID: 106150
02/18/2003 01:11:09PM Session Assigned CSR (Ginny)
02/18/2003 01:11:09PM Enter Session CUS (wizard)
02/18/2003 01:11:25PM Session Accepted CSR (Ginny)
02/18/2003 01:11:25PM Enter Session CSR (Ginny)
02/18/2003 01:11:25PM Message Sent CUS "I was just wondering what the difference is between the DRU-500a and DRU-500ax dvd-rw drives."
02/18/2003 01:11:28PM Message Sent CSR "Hello, my name is Ginny. May I have your full name and phone number please?"
02/18/2003 01:11:50PM Message Sent CUS "(name removed by wizard) xxx-xxx-xxxx"
02/18/2003 01:12:57PM Message Sent CSR "The only difference in those drive is that the DRU 500AX comes with the most recent firmware already installed, the DRU 500A has the latest firmware upgrade available for download."
02/18/2003 01:13:48PM Message Sent CUS "thank you..i was just wondering because i purchased a 500a a few weeks ago...you have been a great help."
02/18/2003 01:14:00PM Message Sent CSR "Thank you for using the Sony Technical Support chat service. In a few minutes, a transcript of your chat session will be emailed to the address that you provided at the time of login. Have a nice day."
02/18/2003 01:15:55PM Leave Session CSR (Ginny)
02/18/2003 01:15:55PM Leave Session CUS
02/18/2003 01:15:55PM Session Ended
If you have any questions, please email
storage.support@am.sony.com, or revisit the
SONY NetAgent System for live support.
as u can see....sony themselves state that the dru-500a and the dru-500ax are the exact same drive and that the only difference is that the 500ax comes already flashed with the newest firmware whereas u have to d/l the newest firmware and flash the 500a yourself. best i can figure about the firmware message on sony site saying the firmware is only for the 500a is that the 500ax does not need to be updated since it already contains the most recent firmware.