SV35.5 Series SATA 250-GB Hard Drive. Seagate SV35.5 Series hard drives are designed to optimize performance while improving reliability and capacity in digital video surveillance systems. 8-MB cache. 24x7 reliability with > 1 million hours MTBF and < 1 percent AFR. Improved data transfer rates (read/write speeds) enabling higher-performance video recording. ATA-7 streaming commands optimize video streaming performance and integrity. Recording of multiple simultaneous video streams while maintaining high data integrity