Dell gets flexible with server memory chips

What Intel's 'Nehalem-EX' is really good for

Two-socket boxes, four-socket memory

The PowerEdge R810 is the entry Nehalem-EX rack box from Dell, and it comes in a 2U form factor, the workhorse for the server industry. Using a feature Dell calls the FlexMem Bridge, this R810 machine, which is technically a four-socket server, can have two of its processor sockets turned off and yet leave their main memory (a total of 16 slots) available to the two sockets that are turned on in the machine. So instead of having a two-socket box that tops out at 256 GB, this one can expand up to the same 512 GB maximum of the M910 blade and the two other true four-socket Nehalem-EX boxes announced by Dell, the R815 and R910.

The R810 can have any of the Nehalem-EX processors in the box, but again, if you use the Xeon 6500s, you can only run them in two sockets. The R810 has six PCI-Express 2.0 peripherals slots (five x8 and one x4) and an extra x4 slot dedicated for a base storage controller. The machine has room for six hot-swap 2.5-inch SAS or SATA drives, and it comes with two 1,100 watt power supplies. Windows and Linux are certified on this box, but Solaris 10 is not.

The default Dell configuration of the R810 comes with two six-core E7540 processors spinning at 2 GHz, 128 GB of memory (using 4 GB memory sticks and fully populating the slots in the box), and three 146 GB SAS disks. It costs $18,636 without an operating system. If you want to go to two sockets of the top-end, eight-core X7560, and then half-populate the box with 16 GB memory sticks for 256 GB total memory, then you're in for $34,591.

The last Dell box is the PowerEdge R910, which is a 4U box with four sockets and up to 64 memory slots, for a top-end 1 TB of main memory. The R910 also includes a failsafe embedded hypervisor, which is a fancy way of saying that the motherboard in the system has redundant embedded flash drives with RAID mirroring. This flash is used to run a server hypervisor, and in the event one of them fries, the server can reboot and gets is hypervisor from the second one. (It is amazing that these were not redundant to begin with, honestly).

The PowerEdge R910 only supports the true Xeon 7500s. Even with 64 memory slots, the 4U chassis can still house up to sixteen front-mounted 2.5-inch SAS or SATA drives. The machine has seven PCI-Express 2.0 slots (one x16, four x8, and two x4) and can be rejiggered to have ten (six x4s and four x8s) if you need it. The R910 can have four 1,100 watt power supplies or four 750 watters that are more energy efficient. Windows and Linux are supported on this box (provided they have the right updates for the Nehalem-EX processors), but again Solaris is not supported.

The default PowerEdge R910 configuration comes with four 2 GHz E7540 processors (each with six cores), 64 of the 2 GB DIMMs (come on, that's crazy), three 146 GB SAS disks, and no operating system. That's a cool $26,905. If you have an extra $92,741 laying around, you can jack the box up to 1 TB using 16 GB sticks, and for a total price of $125,429, that also gets you four of the eight-core X7560s.

Dell does not seem inclined to engineer bigger Nehalem-EX boxes, although that is technically possible, and in the case of eight-socket boxes, it can be done gluelessly and with very little work using the Boxboro chipset.

"We're staying focused on the sweet spot," says Payne. "While it is possible, the opportunity for bigger boxes is shrinking, as it has been for years. As we look at performance and scalability compared to 16-way RISC systems, we think there is a compelling case that can be made with what we have. A four-socket Nehalem-EX can compete."

Bootnote: This story originally said that the PowerEdge R15 was a Xeon 7500 box. It is actually an Opteron 6100 machine, which El Reg will cover separately. ®