I was using this configuration but my PC was freezing the mouse and video by lack of memory, and I had no sensitive increase in sync velocity, so I commented but keep it on file.
Try to decrease it until you find the stable one and keep monitoring your ram.
Try to start at 100 (dbcache=100) and add this "maxmempool=100" then monitor the ram then increase the dbcache if there are still available ram space and put the same value on maxmempool.