It is a known issue with CUPS-1.4.5
http://www.cups.org/str.php?L3535
============================================================
--- scheduler/conf.c	Mon Aug 30 21:18:38 2010
+++ scheduler/conf.c	Wed Oct  3 22:36:53 2012
@@ -540,7 +540,7 @@
 
   cupsdClearString(&DefaultPaperSize);
 
-  cupsdSetString(&RIPCache, "8m");
+  cupsdSetString(&RIPCache, "128m");
 
   cupsdSetString(&TempDir, NULL);
 
--- scheduler/cupsfilter.c	Tue Mar 30 15:07:33 2010
+++ scheduler/cupsfilter.c	Wed Oct  3 22:37:20 2012
@@ -1218,7 +1218,7 @@
   else
     set_string(&FontPath, CUPS_FONTPATH);
 
-  set_string(&RIPCache, "8m");
+  set_string(&RIPCache, "128m");
 
   if ((temp = getenv("CUPS_SERVERBIN")) != NULL)
     set_string(&ServerBin, temp);
--- doc/help/ref-cupsd-conf.html.in	Tue Jul 13 19:43:27 2010
+++ doc/help/ref-cupsd-conf.html.in	Wed Oct  3 22:38:06 2012
@@ -2646,7 +2646,7 @@
 <H3>Examples</H3>
 
 <PRE CLASS="command">
-RIPCache 8m
+RIPCache 128m
 RIPCache 1g
 RIPCache 2048k
 </PRE>
@@ -2657,7 +2657,7 @@
 memory cache used by Raster Image Processor ("RIP") filters such
 as <CODE>imagetoraster</CODE> and <CODE>pstoraster</CODE>. The
 size can be suffixed with a "k" for kilobytes, "m" for megabytes,
-or "g" for gigabytes. The default cache size is "8m", or 8
+or "g" for gigabytes. The default cache size is "128m", or 128
 megabytes.</P>