Sony DRU-800A: Tiger writes only 4x..??


I have a G4/667, been running OS9.2.2. Over the weekend, I bought a Sony DRU-800A DVD burner (16x, DL capable). Under OS9, System Profiler said "disc burning supported". I could play DVD movies, read DVD computer disks.

I bought Tiger today, & after I got it running it appeared as if the DRU-800A was recognized by 10.4 It could read a movie DVD, burn a CD-R (using Burn Disc).

I went ahead & loaded Patchburn 4.0.0a4 & this is what System Profiler says:

Firmware Revision: KY01
Interconnect: ATAPI
Burn Support: Yes (Vendor Supported)
Profile Path: /Library/DiscRecording/DeviceProfiles/PatchBurn-sonydvdrwdru800a.drprofile
Cache: 2048 KB
Reads DVD: Yes
CD-Write: -R, -RW
DVD-Write: -R, -RW, +R, +RW, +R DL
Burn Underrun Protection CD: Yes
Burn Underrun Protection DVD: Yes
Write Strategies: CD-TAO, CD-SAO, CD-Raw, DVD-DAO
Media: No

I used "Burn Disc" to burn a DVD+R (backup some photos), but it did it only at 4x.. Why can't OS X "Burn Disc" burn at a higher rate? How do I get DL capability? ( my discs are single-layer, do I have to put in a DL disc to invoke it?)

I exported a short 30sec video clip from iMovie to iDVD, which burned a disc successfully.

I'm a newbie in terms of DVD burning..I need some more tips on how to fully utilize this 16x DL capable DVD burner.

[ BTW, I got it at Office Depot for $119, less $15 coupon. There's a $30 rebate..$75 net. It comes with highly rated Nero software..PC however ]