diff --git a/bin/ps-graph b/bin/ps-graph
index 51d3fdf..2474838 100755
--- a/bin/ps-graph
+++ b/bin/ps-graph
@@ -4,7 +4,6 @@
 
 hidezone=1	# convert zonenames to "zone-000n"
 cpulimit=10	# scale node size from 0 to cpulimit percent
-ram=$(( $(sysctl -n hw.memsize) / 1000 ))
 
 # For an OS where a single busy process shows pcpu as 100%, such as Linux,
 # cpulimit can be set to 100. You may want to use smaller values, eg, 10, to
@@ -188,7 +187,6 @@ function ps2gv {
             '"`output_colors`"'
             hidezone = '$hidezone'
             cpulimit = '$cpulimit'
-            ram = '$ram'
         }
         $1 != curzone { curzone = $1 }
         $3 > 10  && $3 != "PID" {
@@ -228,7 +226,7 @@ function ps2gv {
                 sizetxt = ""
             } else {
                 if (cpu > cpulimit) { cpu = cpulimit; }
-                ratio = ( mem / ram ) * 10;
+                ratio = mem / 10;
                 width = sprintf("%.2f", 1 + 1.8 * ratio);
                 height = sprintf("%.2f", 0.7 + 2.3 * ratio);
                 sizetxt = " width = \"" width " \" height = \"" height "\" "
@@ -245,4 +243,4 @@ function ps2gv {
 
 [ $(uname -s) = "Darwin" ] && ZONE="sess"
 
-ps -eo ${ZONE:=zone},ppid,pid,rss,pcpu,comm | ps2gv | neato -Tpng -Nfontsize=12 -Elen=1.9 | open -f -a /Applications/Preview.app
+ps -eo ${ZONE:=zone},ppid,pid,pmem,pcpu,comm | ps2gv | neato -Tpng -Nfontsize=12 -Elen=1.9 | open -f -a /Applications/Preview.app