What's the difference between gdal_cachemax and setting the cache size with -wm in gdalwarp?

Question

I'm trying to get better performance out of gdalwarp, and am wondering if there is any difference between setting gdal_cachemax and using the -wm option in gdalwarp?

Answer 1

In document https://trac.osgeo.org/gdal/wiki/UserDocs/GdalWarp the difference is explained in section "Will increasing RAM increase the speed of gdalwarp?"

-wm sets the memory reserved for working buffers of gdalwarp, gdal_cachemax is used for setting the size of i/o buffers. There are more technical details in the section "Warp and Cache Memory: Technical Details".