[robabbott]

Take a look at the HP Moonshot servers for comparison: http://h17007.www1.hp.com/us/en/enterprise/servers/products/...

These boxes have internal slots for 45 blades. The current generation blades are Atoms and run a variety of Linux OS offerings. Future blades will be geared towards memcache, GPU, and other types of clusters. I got a couple of these at work for eval a little while back, and it's a pretty interesting package.

[notacoward]

Actually the closest comparison seems to be Viridis.

http://www.boston.co.uk/solutions/viridis/default.aspx

Both have 12 cards per shelf, each card containing four quad-core ARM processors. The Dell Copper cards are a bit beefier, at 1.6GHz and 8GB and 1.4GHz vs. 4GB for the BL Viridis, OTOH, the Viridis processors are 64-bit and the shelf is 2U instead of 3U, which might more than make up for the other differences.

At that density, the big differentiator is likely to be power (and therefore heat). Viridis claims 5W per server, which is even better than the SiCortex boxes I worked on. I don't see a number for Copper, so my gut tells me it's probably more. The question is how much more.

[ris]

I don't know where you're getting the 64-bit thing from, but beyond that, comparing clock speeds between a Marvell Armada XP and the EnergyCore in the Boston machine is essentially meaningless.

[notacoward]

Yes, you're right, the EnergyCore isn't 64-bit, and of course there are other differences between the architectures. Perhaps you could actually provide some information on how those differences might affect the two systems' capabilities. Or are you just here to snipe at others?

[ris]

My role here is to prevent people going away with misguided information presented as fact and propagating it elsewhere. Or maybe I should just keep my great big trap shut and sit here feeling smug instead.

There is too little information provided on the two examples to be more precise, otherwise I would have gone into it. All we know is the Boston machine is EnergyCore-based - now that could be a 1000 which is Cortex A9 based, or 2000 based which is A15 based - a 3 minute look didn't make it clear which one you were talking about and which servers are based on what. The Dell system just says it's using a Marvell Armada XP. No more information. The Armada XP is (I think) based on a modified A15 core, but of course they won't say this anywhere. I'm guessing this because the XP range claims "64bit memory" which I suppose is their way of saying it has a 64bit physical address space - a feature of the A15 range. Though of course Marvell have an ARM license that would allow them to do something crazy like add PAE to an A9 based core. But I think that's unlikely.

Enough research for you? I would say the only real way to gauge the performance difference between the two is to try your particular application on it.

[notacoward]

In other words, you don't really know enough to say there's a difference. What we do know is that they're the same basic architecture and instruction set, at very similar process levels, so it's not at all unreasonable to estimate that the performance difference is proportional to the clock-rate difference. That clock-rate difference is probably dwarfed both by Viridis's 50% nodes-per-rack advantage and Copper's 2x memory-per-node advantage, so the quibble just wasn't worth it. Thanks for adding so much to the discussion.

[ris]

No - I did not at all say they were very similar. The truth is we have very little to go on to know how much like a Marvell Armada XP is like an A15. In the past, Marvells have been known to be quite different from their stock counterparts.