http://anandtech.com/show/6757/calxedas-arm-server-tested
The main contenders:
Calxeda 24 nodes, each with a quad core Cortex A9 (ECX-1000) @ 1.4GHz, 96GB RAM (4GB x 24, single channel per node)
Dell PE R720 dual socket Xeon E5-2660 (8 cores per chip) @ 2.2GHz, 96GB RAM
(other CPUs are compared, see the link)
As Johan notes, Calxeda's server is more of a cluster than a typical rack server. The performance is interesting. In workloads that it targets, it performs well against the dual Xeon E5-2660 Dell server, beating it in web server tests in both response time and throughput for various loads. Power consumption is 33% lower than the Xeon server under average and peak load (idle power is nearly equal between the ARM and Xeon servers). And this is just with Cortex A9 chips. A15 and A50 should do even better in the future, although using significantly more power.
Sounds great, but then there's the price. $20,000 for the Calxeda 24 node server vs about $8000 for the Dell dual Xeon E5-2660 server. However, if filling a whole rack (and this server is intended for that usage), each Calxeda server comes out to around $8500 each.
Notice that "dirt cheap" ARM processors have close to zero advantage at the server level pricing. Those ECX-1000 chips, if they had GPUs and other things needed in a handheld or tablet processor, would sell for around $20. A Xeon E5-2660 lists for around $1300. Scale makes a huge difference here.
If Intel weren't replacing the aging Atom and coming out with a similar very low power Atom processor for high density server nodes based on the new uarch, this would be very alarming. The 2 pages of simple benchmarks including a dual core Atom are kind of interesting in this light. The ECX-1000 memory bandwidth is very poor and the dual core Atom N2800 has a healthy lead over the quad core A9 based ECX-1000. It should be possible for Silvermont (or later) Atoms to remain power and performance competitive against future Cortex A50 server designs. The 32nm Atom N2800 compared though is a bit of a power hog, relatively speaking, although not as bad as Johan suggests. (Not the same workloads, but 8.5W per ARM node vs 12W for an Atom system isn't too far off.)
The main contenders:
Calxeda 24 nodes, each with a quad core Cortex A9 (ECX-1000) @ 1.4GHz, 96GB RAM (4GB x 24, single channel per node)
Dell PE R720 dual socket Xeon E5-2660 (8 cores per chip) @ 2.2GHz, 96GB RAM
(other CPUs are compared, see the link)
As Johan notes, Calxeda's server is more of a cluster than a typical rack server. The performance is interesting. In workloads that it targets, it performs well against the dual Xeon E5-2660 Dell server, beating it in web server tests in both response time and throughput for various loads. Power consumption is 33% lower than the Xeon server under average and peak load (idle power is nearly equal between the ARM and Xeon servers). And this is just with Cortex A9 chips. A15 and A50 should do even better in the future, although using significantly more power.
Sounds great, but then there's the price. $20,000 for the Calxeda 24 node server vs about $8000 for the Dell dual Xeon E5-2660 server. However, if filling a whole rack (and this server is intended for that usage), each Calxeda server comes out to around $8500 each.
Notice that "dirt cheap" ARM processors have close to zero advantage at the server level pricing. Those ECX-1000 chips, if they had GPUs and other things needed in a handheld or tablet processor, would sell for around $20. A Xeon E5-2660 lists for around $1300. Scale makes a huge difference here.
If Intel weren't replacing the aging Atom and coming out with a similar very low power Atom processor for high density server nodes based on the new uarch, this would be very alarming. The 2 pages of simple benchmarks including a dual core Atom are kind of interesting in this light. The ECX-1000 memory bandwidth is very poor and the dual core Atom N2800 has a healthy lead over the quad core A9 based ECX-1000. It should be possible for Silvermont (or later) Atoms to remain power and performance competitive against future Cortex A50 server designs. The 32nm Atom N2800 compared though is a bit of a power hog, relatively speaking, although not as bad as Johan suggests. (Not the same workloads, but 8.5W per ARM node vs 12W for an Atom system isn't too far off.)