%ps ax | grep speedy_backend | head
5555 ?? Ss 0:00.56 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41012 ?? S 0:04.98 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41043 ?? S 0:05.39 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41046 ?? I 0:01.08 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41053 ?? S 0:04.38 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41054 ?? S 0:01.79 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41060 ?? I 0:00.44 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41061 ?? I 0:00.53 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41062 ?? I 0:00.50 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT
41065 ?? S 0:04.79 /usr/local/bin/speedy_backend -- -M64 -t660 -T/md/tmp/SpeedyT

-M64 ですね。

httpd.conf の設定だと思われ。