diff --git a/testsuite/tests/rts/T18623/all.T b/testsuite/tests/rts/T18623/all.T
index d600b7bde37b9eaa3b9f759e019f23d7d5741735..58ed1a416a1eb73689315606aaf6a25cf0ddb604 100644
--- a/testsuite/tests/rts/T18623/all.T
+++ b/testsuite/tests/rts/T18623/all.T
@@ -8,7 +8,7 @@ test('T18623',
      # Recent versions of osx report an error when running `ulimit -v`
      when(opsys('darwin'), skip),
      when(arch('powerpc64le'), skip),
-     cmd_prefix('ulimit -v ' + str(1024 ** 2) + ' && '),
+     cmd_prefix('ulimit -v ' + str(8 * 1024 ** 2) + ' && '),
      ignore_stdout],
     run_command,
     ['{compiler} --version'])