Plextor PX-Q840U 20x DVD±RW/RAMDVD+R Write Speeds20x, 18x, 16x (CAV)
12x, 8x (P-CAV)
6x, 4x (CLV)DVD+RW Write Speeds8x, 6x (Z-CLV)
4x, 2.4x (CLV)DVD-R Write Speeds20x, 18x, 16x (CAV)
12x, 8x, (P-CAV)
6x, 4x (CLV)DVD-RW Write Speeds6x (Z-CLV)
4x, 2x (CLV)DVD+R DL Write Speeds8x, 6x (Z-CLV)
4x, 2.4x (CLV)DVD-R DL Write Speeds8x, 6x (Z-CLV)
4x, 2x (CLV)DVD-RAM Write Speeds12x, 8x (P-CAV)
6x, 5x, 3x, 2x (CLV)CD Write Speeds48x (CAV)
40x, 32x, 24x (P-CAV)
16x, 8x (CLV)CD Rewrite Speeds32x, 24x (Z-CLV)
16x, 10x, 4x (CLV)DVD Read Speeds16x Max (DVD-ROM Single Layer)
12x Max (DVD-ROM Dual Layer)
16x Max (DVD±R)
12x Max (DVD±RW)
12x Max (DVD±R DL)
12x Max (DVD-RAM)CD Read Speeds48x Max (CD-ROM/CD-R)
40x Max (CD-RW)DAE Speed48x MaxBuffer Size2 MBRandom Access Times
160 ms (CD)
170 ms (DVD)
230 ms (DVD-RAM)CD FormatsCD-DA
CD-ROM
CD-ROM XA
Video CD
Photo CD
CD-Text
CD-I (FMV)
CD-Extra
Multi-Session
CD-R
CD-RWDVD FormatsDVD-ROM
DVD-R/RW
DVD+R/RW
DVD+R DL
DVD-R DL
DVD-RAMCD Recording ModesTrack At Once
Session At Once
Disc At Once
Fixed And Variable Packet WritingDVD+R and DVD+R DL Recording ModesIncremental RecordingDVD+RW Recording ModeRandom Access WriteDVD-R Recording ModesDisc At Once
Incremental RecordingDVD-RW Recording ModesDisc At Once
Restricted Overwrite
Incremental Recording
Sequential RecordingDVD-R DL Recording ModesDisc At Once
Incremental Recording
Layer Jump RecordingDVD-RAM Recording ModeRandom Access Write