diff --git a/sys/amd64/amd64/amd64_mem.c b/sys/amd64/amd64/amd64_mem.c
index 4be3d13dd7a8..90b72b4fcecd 100644
--- a/sys/amd64/amd64/amd64_mem.c
+++ b/sys/amd64/amd64/amd64_mem.c
@@ -575,9 +575,10 @@ static void
 i686_mem_drvinit(void *unused)
 {
     /* Try for i686 MTRRs */
-    if (!strcmp(cpu_vendor, "GenuineIntel") &&
-	cpu_feature & CPUID_MTRR &&
-	(cpu_id & 0xf00) == 0x600) {
+    if ((cpu_feature & CPUID_MTRR) &&
+	((cpu_id & 0xf00) == 0x600) &&
+	((strcmp(cpu_vendor, "GenuineIntel") == 0) ||
+	(strcmp(cpu_vendor, "AuthenticAMD") == 0))) {
 	mem_range_softc.mr_op = &i686_mrops;
     }
 }
diff --git a/sys/i386/i386/i686_mem.c b/sys/i386/i386/i686_mem.c
index 4be3d13dd7a8..90b72b4fcecd 100644
--- a/sys/i386/i386/i686_mem.c
+++ b/sys/i386/i386/i686_mem.c
@@ -575,9 +575,10 @@ static void
 i686_mem_drvinit(void *unused)
 {
     /* Try for i686 MTRRs */
-    if (!strcmp(cpu_vendor, "GenuineIntel") &&
-	cpu_feature & CPUID_MTRR &&
-	(cpu_id & 0xf00) == 0x600) {
+    if ((cpu_feature & CPUID_MTRR) &&
+	((cpu_id & 0xf00) == 0x600) &&
+	((strcmp(cpu_vendor, "GenuineIntel") == 0) ||
+	(strcmp(cpu_vendor, "AuthenticAMD") == 0))) {
 	mem_range_softc.mr_op = &i686_mrops;
     }
 }