diff --git a/INSTALL b/INSTALL
index 0845b15a..36250c1b 100644
--- a/INSTALL
+++ b/INSTALL
@@ -245,9 +245,8 @@ XZ Utils Installation
                 On some systems, there is no code to detect the amount of
                 RAM though. Using --enable-assume-ram one can set how much
                 memory to assume on these systems. SIZE is given as MiB.
-                The default is 32 MiB, which is probably too low for most
-                systems, but it is enough to allow decompressing .xz files
-                created with the default settings.
+                The default is 128 MiB, which allows decompressing files
+                created with "xz -9".
 
                 Feel free to send patches to add support for detecting
                 the amount of RAM on the operating system you use. See
diff --git a/configure.ac b/configure.ac
index bfb64304..af317e93 100644
--- a/configure.ac
+++ b/configure.ac
@@ -348,15 +348,16 @@ AC_MSG_RESULT([$enable_threads])
 # Assumed amount of RAM #
 #########################
 
-# We use 32 MiB as default, because it should be small enough for most
-# cases and allows decompressing files compressed with the default settings.
-# Probably it is too small for most systems, but it's safer to guess too low.
+# We use 128 MiB as default, because it will allow decompressing files
+# created with "xz -9". It would be slightly safer to guess a lower value,
+# but most systems, on which we don't have any way to determine the amount
+# of RAM, will probably have at least 128 MiB of RAM.
 AC_MSG_CHECKING([how much RAM to assume if the real amount is unknown])
 AC_ARG_ENABLE([assume-ram], AC_HELP_STRING([--enable-assume-ram=SIZE],
 		[If and only if the real amount of RAM cannot be determined,
-		assume SIZE MiB. The default is 32 MiB. This affects the
+		assume SIZE MiB. The default is 128 MiB. This affects the
 		default memory usage limit.]),
-	[], [enable_assume_ram=32])
+	[], [enable_assume_ram=128])
 assume_ram_check=`echo "$enable_assume_ram" | tr -d 0123456789`
 if test -z "$enable_assume_ram" || test -n "$assume_ram_check"; then
 	AC_MSG_RESULT([])