Linley Chips In Blog | ARM Outmuscles Atom on Benchmark
ARM–and, for that matter, MIPS–CPUs outperform Intel’s Atom, at least as measured by the CoreMark benchmark when normalized for frequency. ARM rates its Cortex-A9 at 2.9 CoreMark per MHz (CM/MHz), whereas Atom running a single instance of the benchmark achieves only 1.8 CM/MHz. In fact, all of the single-thread CPUs profiled in Table 1 (see below) outperform Atom in terms of per-clock performance
The open question, thus, is which CPUs operate at higher frequencies. Atom is fastest running processor of the lot. The Z550 version is available at 2.0GHz, yielding, we estimate CoreMark performance of 3,673CM. ARM promises its A9 hard core will hit 2.0GHz (Vdd will have to be goosed up), putting its performance beyond that of the Z550. Even if ARM hits only 1.3GHz, its performance will exceed that of the fastest Atom. The fastest A9-based chip available now, Nvidia Tegra 2, hits 1.0GHz, putting it behind the garden-variety Atom N280. MIPS rates its 74K at 1.6GHz in a 40nm G process, putting it also ahead of Z550. We are unaware of any 74K-based chips sampling or in production operating in excess of 1GHz, however.
As with any benchmark comparison, caveats abound. A benchmark only reports how fast a given CPU in a given chip runs the specific benchmark when compiled a certain way. Any conclusion about how well any other program will run on the particular chip is a matter of interpretation, as is any comparison among processors unless conditions are identical. Although the scores below are based on use of the GCC complier, the version used varies as does the compile flags selected. The Atom scores, for example, are for CoreMark compiled with GCC 4.4.1 and O2 optimization and were 5.8% faster than runs when GCC4.3.3 were used. The Cortex-A8 score is based on GCC 4.3.3 with O3. With O2 and GCC 4.3.3, the A8 achieves only 2.2 CM/MHz. Despite the variations in compiler and optimization, the overall conclusions are clear: Cortex-A9 and MIPS 74K will outrun Atom on CoreMark.