bcrypt and qpress seem slower than I would expect.... Advice?

I have a large database I am decrypting and decompressing from a full innobackupex command. I am using the script below to do this. Any suggestions on how to make this go faster, did I miss any ‘speed-up’ options on either of these commands?

This is on centos 6.9, mysql 5.7 and percona-xtrabackup-2.4. The machine has lots of 8 CPU and 60GB of memory. The disks are SSD with a 20MB/second advertised write read/write rate (This is an AWS r2.x4large machine), incase that matters.


<script type="text/bash">
# decrypt_decompress.sh
DATE=$(date '+%Y%m%d_%H%M%S')
time for i in `find /srv/full_backup_20170521/ -iname "*.xbcrypt"`; \
do echo "%%%-INFO: decrypting $i"; \
time xbcrypt -d --encrypt-key-file=/var/lib/mysql/.innobackupex.key --encrypt-algo=AES256 --encrypt-chunk-size=10M < $i \
| qpress -T4di $(dirname $i) \
&& \rm $i; \
) | tee ~/do_decrypt_decompress_${DATE}.log