> In reality I could fill a rack with these arm blades or have two quad socket x86/amd64 servers be equivalent or better
Quad socket x86 is still prohibitively expensive, but in the price per performance assessment you might be right (at least if you do not consider the expensive high-end x86 CPUs). The ARM blades look interesting for bare metal clouds though.
> 4 2U dual socket x86/amd64 boxes still is a better value proposition.
Not if you're aiming at a good density (processing power per rack). But there are many blade options (8 boards in 3U, or 4 in 2U from Supermicro e.g.) for x86 that will fit the bill, yes.
The cost for the vendor should be much lower with ARM CPUs though (the CPUs will probably be dirt cheap, while Intel's aren't).
Context: I'm talking about relative to ARM blades, not denser x86 options.
>The cost for the vendor should be much lower with ARM CPUs though (the CPUs will probably be dirt cheap, while Intel's aren't).
Maybe for the vendor, but these ARM blades boxes are expensive for the consumer!
Lets compare two 2U boxes, one with 48 1.6 GHz ARM SoC and one with dual six-core Xeons with SMT (HT) at lets say 2.8 GHz, that is 48 logical cores. The x86/amd64 box in this comparison is:
0. Much cheaper!
1. Low latency at low loads
2. Similar throughput and latency at high loads
3. Uses less power
4. Easier to maintain
This. Purchasers of the highest-end and/or costly experimental architectures tend to be research institutions or national labs that are using grant money.
In the case of quad-socket, it's actually enterprises running SQL databases and VMware consolidation where the cost of the software license exceeds the cost of the server.
Quad socket x86 is still prohibitively expensive, but in the price per performance assessment you might be right (at least if you do not consider the expensive high-end x86 CPUs). The ARM blades look interesting for bare metal clouds though.