The SATA150 TX4 has four Serial ATA ports and is fitted with a custom chip (PDC20318), which Promise keeps to a reasonable temperature with a small heatsink. We liked the compact size of this controller card, which makes this chip ideal for integrating onto motherboards.

Like the TX2, the TX4 also comes with a manual in five languages, which should make installation easier - even if this aspect is only of major relevance to the uninitiated.

A cable is included for each of the four Serial ATA ports.

The TX4 displayed the same weakness as the TX2 in our interface transfer rate test. When using a motherboard fitted with an Intel Southbridge (i82801DB), the transfer rate peaked at around 63 MBytes/sec. Similarly, the transfer rate rose to 82 MBytes/sec with a board fitted with a VIA chipset. This shows that, in principle, both the TX2 and the TX4 are capable of turning in the desired performance.