Table:
text: Western Digital Raptor
Models
Models
Model_no_ Gen_ Released Capacity Cache_ Interface Feature_set Sector_Size
WD6000BLHX 5 2010 600 GB 32 MB Native SATA 6 Gbit/s NCQ 512 bytes
WD6000HLHX 5 2010 600 GB 32 MB Native SATA 6 Gbit/s NCQ 512 bytes
WD1500HLHX 5 2011 150 GB 32 MB Native SATA 6 Gbit/s NCQ 512 bytes
WD1600HLHX 5 2011 160 GB 32 MB Native SATA 6 Gbit/s NCQ 512 bytes
WD3000HLHX 5 2011 300 GB 32 MB Native SATA 6 Gbit/s NCQ 512 bytes
WD6000HLHX 5 2011 600 GB 32 MB Native SATA 6 Gbit/s NCQ 512 bytes
WD2500HHTZ 6 2012 250 GB 64 MB Native SATA 6 Gbit/s NCQ 4096 bytes
WD5000HHTZ 6 2012 500 GB 64 MB Native SATA 6 Gbit/s NCQ 4096 bytes

Question: What is the 600 GB capacity cache on Western Digital Raptor?