The OP was clearly talking about memory barriers in architectures, not memory models in multi-threaded programming. Don't nitpick. > Memory is shared system s

The OP was clearly talking about memory barriers in architectures, not memory models in multi-threaded programming. Don't nitpick. > Memory is shared system state. To write correct parallel programs, CPUs need to define how they manage consistency between different processors. x86 does have a more conservative model with stronger consistency than ARM, and this does have (theoretical) scaling consequences-- but Intel has a huge amount of experience making it fast. Yeah, but what worries me is not raw throughput scaling; it's power consumption. The mainstream netbooks today: Macbook Air Mid-2012, Chromebook Pixel, and Lenovo X1 Carbon all use the 17W i5-3427U. The MBA Mid-2013 jumped to Haswell early and uses the 15W Core i5-4250U. But we still haven't been able to make a decent quad-core netbook: there's a 15W Core i7-4650U; I believe you can get an MBA 2013 with this as well, but a paltry 1.7 Ghz? How many years has it been since quad-cores first came out? It looks to me like x86 has stagnated: it doesn't matter how competent Intel is; the architecture seems to have fundamental problems. Now, I don't fully understand what the ARM A57 is, but the specs look really impressive [1]. Moreover, AMD has confirmed that they will manufacture Opterons in Q1 2014 [2]. I'm not completely sold on ARM or anything, but there is certainly something interesting going on: and we must investigate. [1]: http://www.arm.com/products/processors/cortex-a50/cortex-a57-processor.php http://www.arm.com/products/processors/cortex-a50/cortex-a57... [2]: http://www.amd.com/us/press-releases/Pages/amd-unveils-2013june18.aspx http://www.amd.com/us/press-releases/Pages/amd-unveils-2013j...