This might help someone i have a SONY DRU500AX dvd burner that no matter what i did would not write at 4x
tried all firmwares
tried different ide cables
even tried it in 2 other computers
tried slave\master etc etc the list of what i tried goes on
contacted sony support they tried a few things when i would not take no for an answer but it still never solved the problem..
anyway just finished building my new rig and put the sony in and you know what it writes ritek datawrite etc all at 4x now
this might prove its not all down to the drive. Im not saying this is the answer to everyone who has this problem but if it helps one person i will be happy..
If anyone wants specs of hardware on old or new system please pm or post
hope this helps..