diff -Nur freebios/src/cpu/p6/mtrr.c freebios.mtrr/src/cpu/p6/mtrr.c
--- freebios/src/cpu/p6/mtrr.c	2002-07-02 15:13:09.000000000 +0800
+++ freebios.mtrr/src/cpu/p6/mtrr.c	2002-08-13 15:36:12.000000000 +0800
@@ -205,6 +205,18 @@
 	unsigned int i;
 	unsigned int fixed_msr = NUM_FIXED_RANGES >> 3;
 	unsigned long low, high;
+	unsigned int tmp;
+
+	// it is recommended that we disable and enable cache when we 
+	// do this. 
+	/* Disable cache */
+	/* Write back the cache and flush TLB */
+	asm volatile ("movl  %%cr0, %0\n\t"
+		      "orl  $0x40000000, %0\n\t"
+		      "wbinvd\n\t"
+		      "movl  %0, %%cr0\n\t"
+		      "wbinvd\n\t":"=r" (tmp)::"memory");
+
 	low = high = 0; /* Shut up gcc */
 	for(i = first; i < last; i++) {
 		/* When I switch to a new msr read it in */
@@ -228,6 +240,11 @@
 	if (fixed_msr < (NUM_FIXED_RANGES >> 3)) {
 		wrmsr(mtrr_msr[fixed_msr], low, high);
 	}
+
+	// turn cache back on. 
+	asm volatile ("movl  %%cr0, %0\n\t"
+		      "andl  $0x9fffffff, %0\n\t"
+		      "movl  %0, %%cr0\n\t":"=r" (tmp)::"memory");
 }
 
 static unsigned fixed_mtrr_index(unsigned long addrk)