Bottom line: The bi-annual Top500 list of the world's most powerful supercomputers was released yesterday, showing some interesting facts: for the first time, only petaflop systems have made the cut; the top two IBM-built machines have retained their positions, and the number of Chinese computers keeps rising while those from the US is falling.

For the first time since the project began in 1993, all 500 supercomputers on the list deliver a petaflop or more on the High Performance Linpack (HPL) benchmark, with the entry level now at 1.022 petaflops.

Summit (148.6 petaflops) and Sierra (94.6 petaflops) have kept their number one and two positions, respectively. Summit boasts 4,356 nodes, each containing two Power9 CPUs with 22 cores and six Nvidia Tesla V100 GPUs, while Sierra has 4,320 nodes that pack two Power9 CPUs and four Nvidia Tesla V100 GPUs each.

The third position is taken by former number one Sunway TaihuLight (93.0 petaflops), developed by China's National Research Center of Parallel Computer Engineering & Technology (NRCPC), while in fourth spot sits another Chinese entry---Tianhe-2A (Milky Way-2A), which uses Intel Xeon and Matrix-2000 processors to reach 61.4 petaflops.

While the US may top the list, China keeps pulling ahead when it comes to overall number of supercomputers. Back in 2017, China took the lead with 202 entries compared to 143 from the US. Now, the number of American machines is down to 116, while its rival has 219. However, thanks to its more powerful systems, the US leads in overall HPL capacity, with 38.4 percent of the aggregate list performance. China is second with 29.9 percent.

It's also good news for American companies. Intel's chips appear in 95.6 percent of all systems, and of the 133 machines that use accelerator or coprocessor technology, 125 use Nvidia GPUs.

As it has more supercomputers overall, China tops the vendor list, with Lenovo claiming 173 systems, followed by Inspur with 71, and Sugon, with 63. Hewlett Packard Enterprises (HPE) is in fourth with 40, but given its acquisition of fifth-place Cray in May, HPE could jump to second spot in the next list.