Form factor	1U Rack.
Processor	Up to two Intel Xeon processor E5-2600 product family CPUs with eight cores (up to 2.9 GHz) or six cores (up to 2.9 GHz) or quad-cores (up to 3.3 GHz). Two QPI links up to 8.0 GT/s each. Up to 1600 MHz memory speed. Up to 20 MB L3 cache.
Chipset	Intel C604.
Memory	Up to 24 DIMM sockets (12 DIMMs per processor). RDIMMs, UDIMMs and LR-DIMMs (Load Reduced DIMMs) supported but memory types cannot be intermixed. Memory DIMM speeds up to 1600 MHz.
Memory maximums	With RDIMMs: Up to 384 GB with 24x 16 GB RDIMMs and two processors With UDIMMs: Up to 64 GB with 16x 4 GB UDIMMs and two processors With LRDIMMs: Up to 768 GB with 24x 32 GB LRDIMMs and two processors
Memory protection	ECC, memory mirroring, and memory sparing.
Disk drive bays	Up to eight 2.5″ hot-swap SAS/SATA HDDs, or up to three 3.5″ hot-swap SAS/SATA HDDs, or up to three 3.5″ Simple Swap SATA HDDs.
Maximum internal storage	Up to 7.2 TB with 900 GB 2.5” SAS HDDs, or up to 8 TB with 1 TB 2.5″ NL SAS/SATA HDDs, or up to 9 TB with 3 TB 3.5″ NL SAS/SATA HDDs. Intermix of SAS/SATA is supported.
RAID support	RAID 0, 1, 10 with H1110, M1115 or M5110. Optional upgrades to RAID 5, 50 available for M1115. Optional upgrades to RAID 5, 50 are available (zero-cache; 512 MB battery-backed cache; 512 MB or 1 GB flash-backed cache) for M5110. Optional upgrade to RAID 6. 60 are available for M5110 with caches.
Optical drive bays	One, optional, for models with 2.5” drives. Support for DVD-ROM or Multiburner.

Tape drive bays	None.
Network interfaces	Four integrated Gigabit Ethernet 1000BASE-T ports (RJ-45); two integrated 10 Gb Ethernet ports (10GBASE-T RJ-45 or 10GBASE-SR SFP+ based) on optional 10 Gb Ethernet mezzanine card (does not consume a PCIe slot)
PCI Expansion slots	Two slots, depending on the riser cards installed. The slots are as follows (all PCIe slots are PCIe 3.0, all PCI-X slots are 64 bit/133 MHz): Slot 1: PCIe x16; low profile, half-length Slot 2: PCIe x8, opt. PCI-X or PCIe x16; full-height/length (req. 2nd CPU) Additional dedicated slot for ServeRAID adapter.
Ports	Two USB 2.0 (three USB 2.0 for 3.5″ HDD models) and one DB-15 video on front. Four USB 2.0, one DB-15 video, one DB-9 serial, one RJ-45 systems management, four RJ-45 GbE network ports, two optional RJ-45 or SFP+ 10 GbE network ports on rear. One internal USB ports (for embedded hypervisor).
Cooling	IBM Calibrated Vectored Cooling™ with up to six N+N redundant hot-swap fans (four standard, additional two with second processor); each fan has two motors.
Power supply	Up to two redundant hot-swap 550 W ac or 750 W ac power supplies (80+ Platinum certification).
Hot-swap parts	Hard drives, power supplies, fans.

Systems management	UEFI, IBM Integrated Management Module 2 (IMM2), Predictive Failure Analysis, Light Path Diagnostics, Automatic Server Restart, IBM Systems Director and IBM Systems Director Active Energy Manager™, IBM ServerGuide. Optional IMM Advanced FOD Upgrade for remote presence (graphics, keyboard and mouse, virtual media).
Security features	Power-on password, administrator’s password, Trusted Platform Module (TPM).
Video	Matrox G200eR2 with 16 MB memory integrated into the IMM2. Maximum resolution is 1600×1200 at 75 Hz with 16 M colors.
Operating systems supported	Microsoft Windows Server 2008 R2 and 2008, Red Hat Enterprise Linux 5 and 6, SUSE Linux Enterprise Server 10 and 11, VMware ESX 4.1 and VMware ESXi 4.1 embedded hypervisor, VMware vSphere 5.
Dimensions	Height: 43 mm (1.7 in), width: 429 mm (16.9 in), depth: 734 mm (28.9 in)
Weight	Minimum configuration: 12.7 kg (28 lb), maximum: 15.9 kg (35.1 lb)

IBM SYSTEM X3550 M4