diff --git a/sys/src/9/pc64/dat.h b/sys/src/9/pc64/dat.h
index 1f5caa736..d188508b0 100644
--- a/sys/src/9/pc64/dat.h
+++ b/sys/src/9/pc64/dat.h
@@ -102,7 +102,7 @@ struct Conf
 	ulong	nmach;		/* processors */
 	ulong	nproc;		/* processes */
 	ulong	monitor;	/* has monitor? */
-	Confmem	mem[4];		/* physical memory */
+	Confmem	mem[16];	/* physical memory */
 	ulong	npage;		/* total physical pages of memory */
 	ulong	upages;		/* user page pool */
 	ulong	nimage;		/* number of page cache image headers */
diff --git a/sys/src/9/pc64/memory.c b/sys/src/9/pc64/memory.c
index a9e9b9c28..37c611e00 100644
--- a/sys/src/9/pc64/memory.c
+++ b/sys/src/9/pc64/memory.c
@@ -44,7 +44,7 @@ struct RMap {
 /* 
  * Memory allocation tracking.
  */
-static Map mapupa[16];
+static Map mapupa[64];
 static RMap rmapupa = {
 	"unallocated unbacked physical memory",
 	mapupa,