Thinkpads Forum

I have an LQE Ultrabay HDD adapter and noticed that the disk read speed is limited to ~75 MiB/s (HD Tune 2.55 read speed bechmark with standard settings). The disk is a 320 GB 7200 rpm model and goes over 100 MiB/s in the same benchmark when sitting in the main disk bay.

Is this limitation due to the non-genuine Ultrabay adapter circuitry, or this expected behavior on original IBM/Lenovo adapters as well?

The Ultrabay "adapter contains a PATA to SATA bridge chip, which means that although the disk is SATA it connects as a PATA (IDE) device".
Source: thinkwiki.org/wiki/Ultrabay_Slim_SATA_HDD_Adapter

This might sufficiently explain the speed difference. Starting with the T400/T500 generation Thinkpads, both HDD connectors are proper SATA.