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Per watt, Raspberry 4 is probably peak CPU of our civilization. But 64-bit is only viable if you buy the twice as expensive 8GB model and have use for the extra
by bullen 6y ago
Per watt, Raspberry 4 is probably peak CPU of our civilization. But 64-bit is only viable if you buy the twice as expensive 8GB model and have use for the extra bandwidth.
I'm building hybrid clusters of 4 (2GB) & 2 (the older version) on 32-bit so I can run my PaaS at record flops/W/$:
https://github.com/tinspin/rupy https://github.com/tinspin/rupy
- coder543 6y ago> But 64-bit is only viable if you buy the twice as expensive 8GB model and have use for the extra bandwidth. Benchmarks don't entirely agree: https://www.cnx-software.com/2016/03/01/64-bit-arm-aarch64-instructions-boost-performance-by-15-to-30-compared-to-32-bit-arm-aarch32-instructions/ https://www.cnx-software.com/2016/03/01/64-bit-arm-aarch64-i... If the difference between AArch64 and AArch32 were simply larger pointers, I would probably agree, but AArch64 includes a number of instructions that can do more work, so 64-bit programs can actually run faster than their 32-bit equivalents, even if you're not using much RAM.
- als0 6y agoAArch64 also has a larger number of registers, which can make a big difference for workloads.
- deleted 6y ago[deleted]
- my123 6y agoPer watt, it's not even close. That's because RPis are a lot behind on manufacturing processes, with newer designs being more efficient too. (RPi4 is on 28nm)
- kev009 6y agoApple has had the performance per watt crown for quite some time. These chips are not very good for anything outside of prototyping, otherwise hyperscalers would run a sea of small nodes.
- genpfault 6y ago> if you buy the twice as expensive 8GB model and have use for the extra bandwidth. Are you seeing increased memory bandwidth on the 8GB version vs. the 1GB/2GB/4GB ones?