LOL and when i say HP i mean OC 
Dell not that it makes much difference as they both design bad SLED usage usually.

well willy, unless you really NEED the other devices on the 
ARMADA XP series SOC  and can live with far less generic speed due to 
the  ARMADA XP series  not having NEON SIMD on board then you are probably far better looking to develop on and for any cortex quad  TI OMAP4 or Samsung Exynos 4 Quad development board today.

 don’t underestimate the importance of having generic NEON SIMD to optimize your code/apps against or do so at your cost in 2012

while its nice to finally see some arm cores in the server space for profit, as usual HP didn’t do a good job of their sled design , remember that its a U3 case and so there is plenty of room in the active PCB space to put far more ARM SOC in there, namely i would have placed at least 8 standard quad ARM cortex SOCS on generic on SO-DIMM form factor  slots in that space alongside more ram slots for a start…
http://138.2.152.197/2011/03/04/toradex-shows-tegra2-computer-on-so-dimm-form-factor/ style that way you can start with half populated slots for the current 4 SOC/16core sled and populated that with more as time passes.

also i see a large problem with HP picking the marvel ARMADA XP series SOC as ARMADA XP do NOT have or ever had a generic NEON SIMD unit inside like all Cortex SOC to date amd so many of the Linaro NEON SIMD optimization’s for all the current ARM linuNEON SIMDx distro’s will OC not function in these servers so making them look slower than they could be in real life workloads , “NO NEON NO good” is the lesson here as even Nvidia discovered and replaced they older SOCs without NEON SIMD PDQ

With HP Redstone server architecture with CalXeda mini servers.
HP is launching a totally new concept for especially web servers which is
according to HP shall be 89 per cent more energy efficient then x86 based servers
and 89% per cent less in volume then x86 based servers.

Dell, is now launching their ARM-based server concept.

And now we will soon see a lot of other server makers to develop similar
ARM-based servers.

But ARM-based servers will be much more energy efficient when ReRAM-memories
will come in production forthcoming years because ReRAM-memories will have all properties
that is good with todays Nand Flash memories but none of it´s poor properties like as
the memory cells loss current and then lose memory bits.
Nand Flash memories have only 100 000 writing cycles and ReRAM have at least
1 000 000 writing cycles but can have 1 000 000 000 writing cycles according to Samsung.

It was about time.