av_sort works just like regular sort, but much faster. Supports these additional command line options :

-v N
Verbosity level. 1 for some information, 2 for lots.
-p N
use N processors. Specifically, have N simultaneous threads doing in-memory sort
-N N
NMERGE. Maximum number of files to merge at once. default=1024
-R MB
approximate RAM (in MB) that sort should try to not exceed. The default is 3/4 of the physical RAM.
-T DIR
-T DIR1,DIR2
If two temp directories are specified, both are used.
else if one is specified, it is used.
else if the environment variable $TMPDIR is specified, that is used.
else /var/tmp is used.
-U ChunkSize
Size of text buffers, or temporary files. Probably only useful for testing.
-V Chunks
Number of temporary files. Probably only useful for testing.
-Z KB
mergealloc -- in kilobytes default=32K
The complete list of options is
Usage: av_sort [OPTION]... [FILE]...
Write sorted concatenation of all FILE(s) to standard output.

+POS1 [-POS2] start a key at POS1, end it *before* POS2 (obsolescent)
field numbers and character offsets are numbered
starting with zero (contrast with the -k option)
-b ignore leading blanks in sort fields or keys
-B buffers total number of simultaneous sort buffers. Default 1 or processors+2.
-c check if given files already sorted, do not sort
-d consider only [a-zA-Z0-9 ] characters in keys
-f fold lower case to upper case characters in keys
-g compare according to general numerical value, imply -b
-i consider only [\040-\0176] characters in keys
-k POS1[,POS2] start a key at POS1, end it *at* POS2
field numbers and character offsets are numbered
starting with one (contrast with zero-based +POS form)
-m merge already sorted files, do not sort
-M compare (unknown) < `JAN' < ... < `DEC', imply -b
-n compare according to string numerical value, imply -b
-N maximum temp files to merge at once, default=1024
-o FILE write result on FILE instead of standard output
-p processors number of simultaneous sort threads to invoke. Default 1
-r reverse the result of comparisons
-R totalMem megabytes of RAM we will try not to exceed. default=100
-s stabilize sort by disabling last resort comparison
-t SEP use SEParator instead of non- to whitespace transition
-T DIRECTORY use DIRECTORY for temporary files, not $TMPDIR or /var/tmp
-T DIR1,DIR2 use two alternating directories for temporary files
-u with -c, check for strict ordering;
with -m, only output the first of an equal sequence
-U as -u, but keep only a unique prefix, i.e. 'a ab abc b' becomes 'a b'
-v write a bunch on nonsence to stderr
-x subFile if using --subexact or --subprefix, write the subtracted lines to subFile
-z end lines with 0 byte, not newline, for find -print0
-Z mergealloc K bytes of mem to use for each read buffer during merge, default=32
--help display this help and exit
--version output version information and exit
--diff do a diff of two files, both assumed to be sorted
--intersect print the intersection of all given (sorted) files
--quicksort use a special quicksort for in-memory sorting (default)
--qsort use the system qsort for in-memory sort
--stablesort use a slower sort that keeps existing order where possible. default if -s is specified
--subexact assuming sorted input, print the first thing minus lines in the second thing
--subprefix assuming sorted input, print the first thing minus lines prefixed by something in the second thing
POS is F[.C][OPTS], where F is the field number and C the character position
in the field, both counted from one with -k, from zero with the obsolescent
form. OPTS is made up of one or more of Mbdfinr; this effectively disables
global -Mbdfinr settings for that key. If no key is given, use the entire
line as the key. With no FILE, or when FILE is -, read standard input.
For yet more information, try "man sort".