It is supported by Dell Technical Support when used with a Dell system.
The double module channel provides high-speed connectivity.Dell PERC H840 RAID Adapter for External MD14XX Only, 8GB NV Cache, Full Height, Customer Install The PERC H840 RAID Controller from Dell offers reliability and performance in addition to providing management with the tolerant disk subsystem failures. This RAID controller offers expandable 4GB storage capacity to improve the performance of your server systems. This product has been tested and validated on Dell systems to ensure compatibility with your computer.