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Quick Take: HP Blade Tops 8-core VMmark w/OC’d Memory

September 25, 2009

HP’s ProLiant BL490c G6 server blade now tops the VMware VMmark table for 8-core systems – just squeaking past rack servers from Lenovo and Dell with a score of 24.54@17 tiles: a new 8-core record. The half-height blade was equipped with two, quad-core Intel Xeon X5570 (Nehalem-EP, 130W TDP) and 96GB ECC Registered DDR3-1333 (12x 8GB, 2-DIMM/channel) memory.

In our follow-up, we found that HP’s on-line configuration tool does not allow for DDR3-1333 memory so we went to the street for a comparison. For starters, we examined the on-line price from HP with DDR3-1066 memory and the added QLogic QMH2462 Fiber Channel adapter ($750) and additional NC360m dual-port Gigabit Ethernet controller ($320) which came to a grand total of $28,280 for the blade (about $277/VM, not including Blade chassis or SAN storage).

Stripping memory from the build-out results in a $7,970 floor to the hardware, sans memory. Going to the street to find 8GB sticks with DDR3-1333 ratings and HP support yielded the Kingston KTH-PL313K3/24G kit (3x 8GB DIMMs) of which we would need three to complete the build-out.  At $4,773 per kit, the completed system comes to $22,289 (about $218/VM, not including chassis or storage) which may do more to demonstrate Kingston’s value in the market place rather than HP’s penchant for “over-priced” memory.

Now, the interesting disclosure from HP’s testing team is this:

Notes from HP's VMmark submission.

Notes from HP's VMmark submission.

While this appears to boost memory performance significantly for HP’s latest run (compared to the 24.24@17 tiles score back in May, 2009) it does so at the risk of running the Nehalem-EP memory controller out of specification – essentially, driving the controller beyond the rated load. It is hard for us to imagine that this specific configuration would be vendor supported if used in a problematic customer installation.

SOLORI’s Take:Those of you following closely may be asking yourselves: “Why did HP choose to over-clock the  memory controller in this run by pushing a 1066MHz, 2DPC limit to 1333MHz?”  It would appear the answer is self-evident: the extra 6% was needed to put them over the Lenovo machine. This issue raises a new question about the VMmark validation process: “Should out of specification configurations be allowed in the general benchmark corpus?” It is our opinion that VMmark should represent off-the-shelf, fully-supported configurations only – not esoteric configuration tweaks and questionable over-clocking practices.

Should there be as “unlimited” category in the VMmark arena? Who knows? How many enterprises knowingly commit their mission critical data and processes to systems running over-clocked processors and over-driven memory controllers? No hands? That’s what we thought… Congratulations anyway to HP for clawing their way to the top of the VMmark 8-core heap…

2 comments

  1. 1333MHz ram is within spec for the x5570. See http://ark.intel.com/Product.aspx?id=37111

    These CPU overclock themselves via “turbo boost”, but only if a few of the cores are idle.

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    • Not quite. Intel specifies DDR3 clock rates based on the number of DIMMs per channel (DPC) – and this is covered well in our article which quotes from Intel specifications (link included):

      https://solori.wordpress.com/2009/04/29/clarification-nehalem-ep-and-ddr3/

      While it is true that Intel’s “turbo boost” allows individual cores to over-clock – provided thermal/power constraints are maintained across the chip – this does not over-clock the memory as you suggest. Since the benchmark we reported on exceeds 1-DPC, it should not – going by Intel’s specification – be allowed to run at DDR3/1333. Again, this is Intel specifications NOT arbitrary limitations imposed by motherboard vendor/OEM.

      Therefore, to deploy this system with settings that exceed CPU vendor limitations on memory seems reckless at best, given that a production implementation of such “memory over-clocking” would be frowned upon by system and software vendors alike (should trouble arise.) To suggest that “valid” benchmarking results can be achieved using such practices is likewise reckless for the enterprise virtualization use case.

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