masterized CD: reading too slow

[mnstudio]

From a while I encounter this problem with masterization of CD:
I burn a data CD (till now with Toast 4.0.5 and from about 2/3 days with 5.0).
When I read it with the same CD-writer (Yamaha CD400t with Toast CD reader) it seems to me there aren't any problems, whilst if I read it from my Mac internal CD-ROM player (Sony 12x) the reading is extremely slow (about 13K /sec.); obviously there is something wrong, also because all older masterized CDs (masterized about 1month ago) can be read fine on both CD readers.
The same happens for Audio CDs: the olders (jam-masterized ones) can be extracted (with Toast CD Extractor) fine on both CD readers, whilst the newers (WaveBurner Pro masterized-ones) are too slow.
Does anyone know how I can solve this problem? http://www.audioforums.com/forums/frown.gif-
Thanks
Ciao
Fulvio
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PowerMac 7500/G3/300/150
LAMP 4.7.2 SD 3.0.4
MAc Os 8.6 336 Meg RAM
1stHDAudio: Quantum Atlas 2Gb
2ndHDAudio: Seagate ST39204LW 9Gb
Ultra3 SCSI bus: Atto PCI UL3D
Digi001/DAE 5.0.1
Sony DMX-R100/ADAT card DMBK-R106