62 Planning, Installing, and Managing the IBM System x3950 M22.4 Comparing x3950 M2 to x3950The x3950 M2 has the ability to scale to more than four processor sockets similarto its predecessors, the System x3950 and the xSeries 460. It has twice thenumber of memory slots (from 16 to 32), and benefits from the increased numberof supported processor cores (from 8 to 24 cores), and increased front-side busbandwidth (from 667 MHz to 1066 MHz). It also derives benefits from adedicated front-side bus for each multi-core processors as compared to thex3950 and x460 which used a shared front-side bus for each pair of processorsockets.For multinode configurations, the x3950 M2 scales to a four-node configurationwith potentially more cores (up to 96 cores) than the maximum eight nodespossible with the x3950 (at most 64 cores).The Hurricane 4 chipset also adds improved bandwidth for its three scalabilityports and has increased memory throughput with eight high speed memorybuffer chips. Furthermore, the x3950 M2 has support for more I/O slots frompreviously having six PCI-X slots to seven PCIe slots.The onboard LSI 1078 RAID controller and the optional ServeRAID MR10kinstalled in a dedicated PCIe x8 slot have significantly improved storagesubsystem bandwidth compared to the x3950’s Adaptec ServeRAID 8i RAIDcontroller which shared a slower common PCI-X 66 MHz bus to the Southbridgewith the onboard Broadcom Gigabit Ethernet controllers. The Hurricane 4 has adedicated Enterprise Southbridge Interface (ESI) for the dual port onboard PCIex4 Broadcom 5709C controllers, RSA II, Video, USB 2.0 and Serial interfaces.The x3950 M2 also has an onboard 4x SAS port which can be used inconjunction with the ServeRAID MR10k for additional disk drive expansion (forexample, using one or more EXP3000 storage enclosures) not previouslypossible with the x3950.Table 2-2 on page 63 compares the major differences between the x3950 M2and the x3950.Trusted Platform Module(TPM)None TPM with TCG V1.2compliancePower supplies One or two 1300 W powersupplies, depending onmodelTwo 1440 W powersuppliesFeature System x3850 server System x3850 M2 server