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by eanzenberg 2976 days ago
The impression I got was opposite: TPU is not the hot shit that Google claims it is. Pricing is kind of irrelevant since they can subsidize this to create that story.
3 comments

I know an engineer who prototypes GPU-like systems with FPGA and he has told me to be skeptical about performance miracles.

No matter how fast a system is on the inside you have to get data in and out of it -- at the very least to memory. SRAM takes too much area and there is a limit DRAM bandwidth despite technologies such as eDRAM and HBM. Some tasks are compute intensive, but for general tasks, a processor that is 100x faster would need 100x faster memory to really be 100x faster.

Thus advances in real-life performance are likely to be more like a factor of 2.

For training I never pay full price in the AWS cloud, rather I run interruptable instances and pay a fraction of the list price. People I know who train in the Google cloud seem to get interrupted all the time even though they are paying full price.

Inference is another story. Once you have the trained model, you will usually need to run inference many many more times than you run training and this gets more so the bigger scale you are running at. That hits your unit costs and it is where you need to pinch every penny.

> Pricing is kind of irrelevant since they can subsidize this to create that story.

Depends on how much you plan to use the hardware. If it's running near continuously, total cost of ownership is very important. Power costs can quickly dominate TCO.

At the pricing extreme, Google could make their TPUs free to use and charge elsewhere in their cloud. This shows that literal pricing is pretty irrelevant.
So could AWS/Nvidia.
AWS yes. Nvidia, not so sure. When you buy a 1080ti you are competing with gamers and miners (and maybe others). There's nothing to subsidize, in fact those cards are selling above MSRP, because they aren't selling an ecosystem but a physical card.
> When you buy a 1080ti you are competing with gamers and miners (and maybe others). There's nothing to subsidize, in fact those cards are selling above MSRP, because they aren't selling an ecosystem but a physical card.

Those cards are also irrelevant to the comparison as they can't be bought in large capacities for ML workloads. We're talking about Titan-V's and DGX-1's here.

Are you suggesting the Titan-V price is subsidized by Nvidia?
Did you get that impression from this line in the article?

> While the V100s perform similarly fast, the higher price and slower convergence of the implementation results in a considerably higher cost-to-solution.