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I wonder how competitive GPU's would be with FPGA's on this type of problem. FPGA's have the advantage that the circuit architecture can be designed specifical

I wonder how competitive GPU's would be with FPGA's on this type of problem. FPGA's have the advantage that the circuit architecture can be designed specifically for the algorithm but as far as I know they have much lower gate density and clock speeds compared to top of the line GPU's. In the case of bitcoin mining as far as I know GPU's passed the hat directly to ASIC's. I never heard that FPGA's were competitive for that.

blattimwind 6y ago
> In the case of bitcoin mining as far as I know GPU's passed the hat directly to ASIC's. I never heard that FPGA's were competitive for that. They were, before the ASICs came. CPU -> GPU -> FPGA -> ASIC. A classic story of specialization.
- Taek 6y ago
  Ehhh not really. There was some FPGA mining that happened in Bitcoin but it was always niche rather than at-scale. FPGAs are a lot better than GPUs from the perspective of energy efficiency, but the FPGAs themselves are very expensive to purchase, and are a lot more specialized than GPUs. ASICs showed up before FGPAs ever really took off, and even if ASICs hadn't showed up it's not clear that FGPAs would have been superior on a total-cost basis to GPUs except in niche circumstances.
  - tgflynn 6y ago
    > are a lot more specialized than GPUs. What do you mean by "more specialized" ? FPGA's can implement any logic circuit whereas GPU's are optimized for highly parallel arithmetic computations. I don't understand how that makes FPGA's "more specialized". It seems like they are in fact more general.
    - jkhdigital 6y ago
      They are specialized in generality /s
    - dooglius 6y ago
      FPGA designs can be more specialized than GPU kernels, because FPGAs are more general than GPUs.
    - wmf 6y ago
      You can't buy FPGAs at Fry's and you can't use them for gaming when you're not mining.
Taek 6y ago
GPUs do have much better gate density, and better clock speeds, but the problem here is so specialized that the improved raw speeds of a GPU don't remotely make up for its inflexibility. Additionally, GPUs are optimized for throughput. CPUs are optimized for latency, I haven't seen the benchmarks but I'd blindly bet that a modern CPU could get lower latency on this problem than a modern GPU. The blog post here solved the entire problem in just 3 clock cycles. I don't know how the numbers come back on a GPU or CPU, but the vast majority of the optimizations here are completely impossible on a standard instruction set, and would instead require doing dozens to hundreds of clock cycles. Going from 65 MHz to 5 GHz isn't going to make up for all the shortcuts you lose out on.

blattimwind 6y ago

> In the case of bitcoin mining as far as I know GPU's passed the hat directly to ASIC's. I never heard that FPGA's were competitive for that. They were, before the ASICs came. CPU -> GPU -> FPGA -> ASIC. A classic story of specialization.

Taek 6y ago
Ehhh not really. There was some FPGA mining that happened in Bitcoin but it was always niche rather than at-scale. FPGAs are a lot better than GPUs from the perspective of energy efficiency, but the FPGAs themselves are very expensive to purchase, and are a lot more specialized than GPUs. ASICs showed up before FGPAs ever really took off, and even if ASICs hadn't showed up it's not clear that FGPAs would have been superior on a total-cost basis to GPUs except in niche circumstances.
- tgflynn 6y ago
  > are a lot more specialized than GPUs. What do you mean by "more specialized" ? FPGA's can implement any logic circuit whereas GPU's are optimized for highly parallel arithmetic computations. I don't understand how that makes FPGA's "more specialized". It seems like they are in fact more general.
  - jkhdigital 6y ago
    They are specialized in generality /s
  - dooglius 6y ago
    FPGA designs can be more specialized than GPU kernels, because FPGAs are more general than GPUs.
  - wmf 6y ago
    You can't buy FPGAs at Fry's and you can't use them for gaming when you're not mining.

Taek 6y ago

GPUs do have much better gate density, and better clock speeds, but the problem here is so specialized that the improved raw speeds of a GPU don't remotely make up for its inflexibility. Additionally, GPUs are optimized for throughput. CPUs are optimized for latency, I haven't seen the benchmarks but I'd blindly bet that a modern CPU could get lower latency on this problem than a modern GPU. The blog post here solved the entire problem in just 3 clock cycles. I don't know how the numbers come back on a GPU or CPU, but the vast majority of the optimizations here are completely impossible on a standard instruction set, and would instead require doing dozens to hundreds of clock cycles. Going from 65 MHz to 5 GHz isn't going to make up for all the shortcuts you lose out on.