MapTiler is a multi-threaded program. The modern CPUs has multiple cores and support of Hyperthreading which provides multiple logical CPUs per core. This way MapTiler can provide higher performance even on a dual-core computer.
Upgrade to a higher plan
The Free version is limited to 1 CPU, MapTiler Start and Plus have a limit of 2 CPUs for rendering, which doubles the rendering speed.
The Pro version is able to render on 4 or more CPUs depending on your license. With such power, it is easily able to render extremely large datasets (e.g. continents or the whole world).
The number of purchased CPUs is automatically detected and if the computer is capable of faster rendering, it is possible to purchase additional CPUs for higher rendering speed. The information about the number of CPUs and possible upgrade is available in File -> License… or it is visible during rendering.
Optimize your workflow
Apart from buying more CPUs, you can also reach the speed gain by optimizing your workflow, especially for a large amount of data. MapTiler is most effective reading 256x256 blocks of data.
For large rasters, a tile based format (as opposed to scanline-based) will drastically speed up processing. A block size that is similar to the tile output size e.g. 256x256 or 512x512 will dramatically speed up the processing time. Also, consider adding overviews o the raster file.
Both can be done using command-line tools of the GDAL library, such as gdalwarp and gdaladdo
You may be using the Cloud Optimized GeoTIFF format (COG), which does contain all mentioned optimizations. “gdalwarp -of COG -co COMPRESSION=DELFATE input.tiff output.tiff”