[MindSpunk]

Yes and it's very slow as a result. In-order cores without speculative execution can't be fast. Not unless you have no memory and only operate out of something equivalent to L1 cache.

Memory is slow. Insanely slow (compared to the CPU). You can process stupid fast if your entire working set can fit in a 2KB L1 cache, but the second you touch memory you're hosed. You can't hide memory latency without out-of-order execution and/or SMT. You fundamentally need to be parallel to hide latency. CPUs do it with out-of-order and speculative execution. GPUs do it by being stupidly parallel and running something like 32-64 way SMT (huge simplification). Many high-performance CPUs do all of these things.

Instruction level parallelism is simply not optional with the DRAM latency we have.

[happosai]

Cortex a53 may be slow, but it's fast enough for very many tasks. Once you design the your data structures to fit L1/L2 caches it actually is pretty damn fast. Best part of cache aware data structure design it also makes code run faster on Out Of Order CPUS. A53 is of course slow if you use modern layer-upon-layer-ware as your architecture.

But I was just really trying to point that in-order cpus are still around, they did not disappear with in-order atom.