diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index f90ad03a591..00aa47247b0 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1309,7 +1309,7 @@ getmemsize(caddr_t kmdp, u_int64_t first)
 {
 	int i, physmap_idx, pa_indx, da_indx;
 	vm_paddr_t pa, physmap[PHYSMAP_SIZE];
-	u_long physmem_tunable;
+	u_long physmem_tunable, memtest, tmpul;
 	pt_entry_t *pte;
 	struct bios_smap *smapbase, *smap, *smapend;
 	u_int32_t smapsize;
@@ -1371,6 +1371,14 @@ getmemsize(caddr_t kmdp, u_int64_t first)
 	if (TUNABLE_ULONG_FETCH("hw.physmem", &physmem_tunable))
 		Maxmem = atop(physmem_tunable);
 
+	/*
+	 * By default keep the memtest enabled.  Use a general name so that
+	 * one could eventually do more with the code than just disable it.
+	 */
+	memtest = 1;
+	if (TUNABLE_ULONG_FETCH("hw.memtest.tests", &tmpul))
+		memtest = tmpul;
+
 	/*
 	 * Don't allow MAXMEM or hw.physmem to extend the amount of memory
 	 * in the system.
@@ -1433,6 +1441,8 @@ getmemsize(caddr_t kmdp, u_int64_t first)
 				goto do_dump_avail;
 
 			page_bad = FALSE;
+			if (memtest == 0)
+				goto skip_memtest;
 
 			/*
 			 * map page into kernel: valid, read/write,non-cacheable
@@ -1470,6 +1480,7 @@ getmemsize(caddr_t kmdp, u_int64_t first)
 			 */
 			*(int *)ptr = tmp;
 
+skip_memtest:
 			/*
 			 * Adjust array of valid/good pages.
 			 */
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 91050c43bee..73e75513768 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -2132,7 +2132,7 @@ static void
 getmemsize(int first)
 {
 	int has_smap, off, physmap_idx, pa_indx, da_indx;
-	u_long physmem_tunable;
+	u_long physmem_tunable, memtest, tmpul;
 	vm_paddr_t physmap[PHYSMAP_SIZE];
 	pt_entry_t *pte;
 	quad_t dcons_addr, dcons_size;
@@ -2339,6 +2339,14 @@ physmap_done:
 	if (has_smap && Maxmem > atop(physmap[physmap_idx + 1]))
 		Maxmem = atop(physmap[physmap_idx + 1]);
 
+	/*
+	 * By default keep the memtest enabled.  Use a general name so that
+	 * one could eventually do more with the code than just disable it.
+	 */
+	memtest = 1;
+	if (TUNABLE_ULONG_FETCH("hw.memtest.tests", &tmpul))
+		memtest = tmpul;
+
 	if (atop(physmap[physmap_idx + 1]) != Maxmem &&
 	    (boothowto & RB_VERBOSE))
 		printf("Physical memory use set to %ldK\n", Maxmem * 4);
@@ -2402,6 +2410,8 @@ physmap_done:
 				goto do_dump_avail;
 
 			page_bad = FALSE;
+			if (memtest == 0)
+				goto skip_memtest;
 
 			/*
 			 * map page into kernel: valid, read/write,non-cacheable
@@ -2439,6 +2449,7 @@ physmap_done:
 			 */
 			*(int *)ptr = tmp;
 
+skip_memtest:
 			/*
 			 * Adjust array of valid/good pages.
 			 */
diff --git a/sys/pc98/pc98/machdep.c b/sys/pc98/pc98/machdep.c
index 8bcb618759a..22131a625b8 100644
--- a/sys/pc98/pc98/machdep.c
+++ b/sys/pc98/pc98/machdep.c
@@ -1855,7 +1855,7 @@ static void
 getmemsize(int first)
 {
 	int off, physmap_idx, pa_indx, da_indx;
-	u_long physmem_tunable;
+	u_long physmem_tunable, memtest, tmpul;
 	vm_paddr_t physmap[PHYSMAP_SIZE];
 	pt_entry_t *pte;
 	quad_t dcons_addr, dcons_size;
@@ -1915,6 +1915,14 @@ getmemsize(int first)
 	if (TUNABLE_ULONG_FETCH("hw.physmem", &physmem_tunable))
 		Maxmem = atop(physmem_tunable);
 
+	/*
+	 * By default keep the memtest enabled.  Use a general name so that
+	 * one could eventually do more with the code than just disable it.
+	 */
+	memtest = 1;
+	if (TUNABLE_ULONG_FETCH("hw.memtest.tests", &tmpul))
+		memtest = tmpul;
+
 	if (atop(physmap[physmap_idx + 1]) != Maxmem &&
 	    (boothowto & RB_VERBOSE))
 		printf("Physical memory use set to %ldK\n", Maxmem * 4);
@@ -1991,6 +1999,8 @@ getmemsize(int first)
 				goto do_dump_avail;
 
 			page_bad = FALSE;
+			if (memtest == 0)
+				goto skip_memtest;
 
 			/*
 			 * map page into kernel: valid, read/write,non-cacheable
@@ -2028,6 +2038,7 @@ getmemsize(int first)
 			 */
 			*(int *)ptr = tmp;
 
+skip_memtest:
 			/*
 			 * Adjust array of valid/good pages.
 			 */