diff --git a/configs/common/Benchmarks.py b/configs/common/Benchmarks.py
index 9a1657e01..d1c69d3f8 100644
--- a/configs/common/Benchmarks.py
+++ b/configs/common/Benchmarks.py
@@ -27,6 +27,7 @@
 # Authors: Ali Saidi
 
 from SysPaths import *
+from m5.defines import buildEnv
 
 class SysConfig:
     def __init__(self, script=None, mem=None, disk=None):
@@ -49,8 +50,14 @@ class SysConfig:
     def disk(self):
         if self.diskname:
             return disk(self.diskname)
-        else:
+        elif buildEnv['TARGET_ISA'] == 'alpha':
             return env.get('LINUX_IMAGE', disk('linux-latest.img'))
+        elif buildEnv['TARGET_ISA'] == 'x86':
+            return env.get('LINUX_IMAGE', disk('x86root.img'))
+        else:
+            print "Don't know what default disk image to use for ISA %s" % \
+                buildEnv['TARGET_ISA']
+            sys.exit(1)
 
 # Benchmarks are defined as a key in a dict which is a list of SysConfigs
 # The first defined machine is the test system, the others are driving systems
diff --git a/configs/common/FSConfig.py b/configs/common/FSConfig.py
index 53ab06813..f13b90e9e 100644
--- a/configs/common/FSConfig.py
+++ b/configs/common/FSConfig.py
@@ -293,7 +293,6 @@ def makeX86System(mem_mode, numCPUs = 1, mdesc = None, self = None):
     if not mdesc:
         # generic system
         mdesc = SysConfig()
-    mdesc.diskname = 'x86root.img'
     self.readfile = mdesc.script()
 
     self.mem_mode = mem_mode