diff --git a/syncoid b/syncoid
index 956f3e7..e908a6c 100755
--- a/syncoid
+++ b/syncoid
@@ -17,6 +17,9 @@ use Capture::Tiny ':all';
 
 my $mbuffer_size = "16M";
 my $pvoptions = "-p -t -e -r -b";
+# Get number of CPUs for zstd threading, but leave at least two cores empty for system responsiveness
+my $ncpus = int(`nproc`);
+if ($ncpus > 2) { $ncpus -= 2;}
 
 # Blank defaults to use ssh client's default
 # TODO: Merge into a single "sshflags" option?
@@ -1141,10 +1144,16 @@ sub compressargset {
 			decomargs   => '-dc',
 		},
 		'zstd-fast' => {
-			rawcmd      => 'zstd',
-			args        => '-3',
-			decomrawcmd => 'zstd',
-			decomargs   => '-dc',
+                        rawcmd      => 'zstd',
+                        args        => "-T$ncpus -3",
+                        decomrawcmd => 'zstd',
+                        decomargs   => "-T$ncpus -dc",
+		},
+		'zstd-medium' => {
+                        rawcmd      => 'zstd',
+                        args        => "-T$ncpus -8",
+                        decomrawcmd => 'zstd',
+                        decomargs   => "-T$ncpus -dc",
 		},
 		'zstdmt-fast' => {
 			rawcmd      => 'zstdmt',
@@ -1153,10 +1162,10 @@ sub compressargset {
 			decomargs   => '-dc',
 		},
 		'zstd-slow' => {
-			rawcmd      => 'zstd',
-			args        => '-19',
-			decomrawcmd => 'zstd',
-			decomargs   => '-dc',
+                        rawcmd      => 'zstd',
+                        args        => "-T$ncpus -19",
+                        decomrawcmd => 'zstd',
+                        decomargs   => "-T$ncpus -dc",
 		},
 		'zstdmt-slow' => {
 			rawcmd      => 'zstdmt',
@@ -1186,7 +1195,7 @@ sub compressargset {
 
 	if ($value eq 'default') {
 		$value = $DEFAULT_COMPRESSION;
-	} elsif (!(grep $value eq $_, ('gzip', 'pigz-fast', 'pigz-slow', 'zstd-fast', 'zstdmt-fast', 'zstd-slow', 'zstdmt-slow', 'lz4', 'xz', 'lzo', 'default', 'none'))) {
+	} elsif (!(grep $value eq $_, ('gzip', 'pigz-fast', 'pigz-slow', 'zstd-fast', 'zstd-medium', 'zstdmt-fast', 'zstd-slow', 'zstdmt-slow', 'lz4', 'xz', 'lzo', 'default', 'none'))) {
 		writelog('WARN', "Unrecognised compression value $value, defaulting to $DEFAULT_COMPRESSION");
 		$value = $DEFAULT_COMPRESSION;
 	}
@@ -2400,7 +2409,7 @@ syncoid - ZFS snapshot replication tool
 
 Options:
 
-  --compress=FORMAT     Compresses data during transfer. Currently accepted options are gzip, pigz-fast, pigz-slow, zstd-fast, zstdmt-fast, zstd-slow, zstdmt-slow, lz4, xz, lzo (default) & none
+  --compress=FORMAT     Compresses data during transfer. Currently accepted options are gzip, pigz-fast, pigz-slow, zstd-fast, zstd-medium, zstdmt-fast, zstd-slow, zstdmt-slow, lz4, xz, lzo (default) & none
   --identifier=EXTRA    Extra identifier which is included in the snapshot name. Can be used for replicating to multiple targets.
   --recursive|r         Also transfers child datasets
   --skip-parent         Skips syncing of the parent dataset. Does nothing without '--recursive' option.