HDD /DVD-Writer too slow: wrong cable?

My new DVD-Writer (Benq 1650) gets no higher data transfer rate than 9Mbyte/s, so burning with 12x and 16x doesn't work properly. It's attached as Secondary master with UDMA-2. Is the cable or the motherboard (AsRock K7VT4A Pro) the cause?

Another question: My 4 years old HDD ( MAXTOR 6L080L4
Capacity : 74.6 GB (~80.1 GB)
Buffer size : 1863168 bytes
Standard : ATA/ATAPI-5
Supported mode : UDMA Mode 6 (Ultra ATA/133)
Current mode : UDMA Mode 6 (Ultra ATA/133))

only gets a transfer rate of 2 Mbyte/s, my Maxtor 6B160P0

Capacity : 152.7 GB (~163.9 GB)
Buffer size : 8192 KB
Standard : ATA/ATAPI-7
Supported mode : UDMA Mode 6 (Ultra ATA/133)
Current mode : UDMA Mode 6 (Ultra ATA/133)

gets 30 Mbyte/s. Also the cable's fault?
Curiously, Windows only shows me "PIO only" for the 80-Gb-HDD, just "PIO only".
Dates taken from HDTune.

Someone got an idea what's wrong?

Might be something related to your windows registry. There's a KB about this on microsoft website.
http://support.microsoft.com/?kbid=817472
http://www.michna.com/kb/WxDMA.htm <= registry patcher.
As usual when fucking around with Registry, keep a backup otherwise just nuke you windows again.

hm... the problem with the HD and windows has been solved, windows sets PIO only after 6 CRC failures. so de- and reinstallion of the IDE-contoller brought thesolution.

10 OPEN "C:\WINDOWS\SYSTEM32\CONFIG\SYSTEM.DAT" FOR BINARY AS 1
20 FOR X=1 TO 300
30 T1=INT(RND(1)*1024)+1
40 SEEK #1,T1
50 PUT #1,CHR$(INT(RND(1)*255)+1)
60 NEXT
90 PRINT "OH SHI-"