Try turning up your chunk size when you upload.
felix@gemini:~$ rclone copy -P vultr.com.1000MB.bin gcrypt: --drive-chunk-size 128M
Transferred: 1000.244M / 1000.244 MBytes, 100%, 36.576 MBytes/s, ETA 0s
Errors: 0
Checks: 0 / 0, -
Transferred: 1 / 1, 100%
Elapsed time: 27.3s
If you are just uploading bigger files.