Performance tips

Nextclade algorithms are computationally expensive and require a lot of CPU cycles and system memory (RAM). All this computational work runs on your computer, in the web browser.

Here are some things to try if you experience performance problems, i.e. if Nextclade is slow or crashes.

For the best experience and performance, it is advised to run Nextclade in one of the latest versions of Firefox or Chrome web browsers, as they are known for the fastest and the most spec-compliant implementations of the web technologies that Nextclade uses.

Browser extensions, such as ad blockers, can interfere with Nextclade software modules and may cause slowdown, excessive memory consumption and crashes. Nextclade does not serve ads. Try to disable them selectively for the Nextclade website.

For optimal performance, before running Nextclade, close unused applications and browser tabs, especially tabs with extra copies of Nextclade, in order to free up the system memory they are occupying.

You can also try to tune the performance by increasing or decreasing the number of CPU threads in the “Settings” window. This option tells Nextclade how many processing jobs it is allowed to run in parallel. More threads will consume more memory, and will make startup process longer, but will make the analysis faster in case there are many sequences to process. Less threads will speedup the startup, and decrease memory consumption, but will make the analysis slower.

In case of any problems, try to run Nextclade in a fresh private/incognito browser window, with no extensions enabled, and where Nextclade is the only tab.

Lagging results page

When analyzing many sequences with many hundreds of mutations, the results page may become slow because of the large number of mutation markers that are displayed. If you experience this problem, reduce the number Max. nucleotide markers in Settings -> Sequence view.