Nvidia has called out Intel for juicing its chip performance in specific benchmarks—accusing Intel of publishing some incorrect "facts" about the performance of its long-overdue Knights Landing Xeon Phi cards.

Nvidia's primary beef is with the following Intel slide, which was presented at a high performance computing conference (ISC 2016). Nvidia disputes Intel's claims that Xeon Phi provides "2.3x faster training" for neural networks and that it has "38 percent better scaling" across nodes.

At this juncture I should point out that juicing benchmarks is, rather sadly, par for the course. Whenever a chip maker provides its own performance figures, they are almost always tailored to the strength of a specific chip—or alternatively, structured in such a way as to exacerbate the weakness of a competitor's product.

In this case, it looks like Intel opted for the classic using-an-old-version-of-some-benchmarking-software manoeuvre. Intel claimed that a Xeon Phi system is 2.3 times faster at training a neural network than a comparable Maxwell GPU system; Nvidia says that if Intel used an up-to-date version of the benchmark (Caffe AlexNet), the Maxwell system is actually 30 percent faster. And of course, Maxwell is Nvidia's last-gen part; the company says a comparable Pascal-based system would be 90 percent faster.

On the 38-percent-better-scaling point, Nvidia says that Intel compared 32 of its new Xeon Phi servers against four-year-old Nvidia Kepler K20 servers being used in ORNL's Titan supercomputer. Nvidia states that modern GPUs, paired with a newer interconnect, scale "almost linearly up to 128 GPUs."

In short, Nvidia is adamant that for high-performance computing—and specifically deep-learning applications—you should use GPUs rather than Knights Landing Xeon Phi (which is essentially 72 Atom CPUs on a chip, with two AVX-512 vector units strapped to each core that do most of the heavy lifting).

We've asked Intel if it has a response or rebuttal to Nvidia's fightin' words, but haven't yet heard back.

Update @ 17:30 BST. Intel responded to your request for comment with the following: "It is completely understandable that Nvidia is concerned about Intel in this space. Intel routinely publishes performance claims based on publicly available solutions at the time, and we stand by our data."

This story is a fine example of why we always do our own benchmarking when reviewing products: to make sure the numbers are fair and just. Sometimes you can't even rely on benchmarks, though: over the years, both Nvidia and ATI/AMD have cheated their way to artificially high performance figures with "optimised" drivers that include code specifically for benchmarking suites like 3D Mark.