IBM System x3650 M2

The majority of businesses buy 2U rack servers because they want a good combination of performance, storage capacity and expansion potential. IBM's latest x3650 M2 certainly looks to have these features in abundance, and in this review we see how well it stands up to the PC Pro A-Listed ProLiant DL380 G6, which HP claims is the world's favourite 2U rack server.

The x3650 matches HP for build quality, as the chassis is well constructed and feels solid. It also comes a close second for storage capacity, as the main hard disk bay supports up to eight hot-swap SFF hard disks. Remove the small filler panel alongside and you can add four more drives. The DL380 G6 can handle up to 16 SFF drives, whereas Dell's PowerEdge R710 can manage only eight in total.

For expansion, IBM offers a four-bay simple swap module or the 4-Pac HDD hot-swap option kit: this includes a SAS expander, allowing all 12 bays to be managed by one controller. Moving the bays across to the right also makes room for an optional SAS tape drive.

RAID card choices are good, as the base model comes with a dual-port ServeRAID PCI Express card fitted behind the bay and supporting stripes and mirrors. This can be upgraded with cache memory and support for RAID5 and 6 arrays, and IBM offers a battery backup pack as well. The review system included the 256MB cache and BBU upgrade, but you can go up to 512MB cache.

Virtualisation gets more than a passing nod since the riser card for the RAID controller has an internal USB port, which can be used to add a bootable storage device for loading VMware ESXi 3.5. HP and Dell do score better here, since both their 2U rack servers have internal SD card slots for this function.

Initial installation is made easier, as IBM's new UEFI (unified extensible firmware interface) provides access to a setup menu for server configuration, a boot device manager and a diagnostics GUI. However, you still need to boot the server with the ServerGuide disc to install an OS. Dell's Lifecycle Controller and UEFI have these tools embedded, so you don't need the startup disc anymore.