diff --git a/dlls/wined3d/resource.c b/dlls/wined3d/resource.c
index b76783f..1ddb275 100644
--- a/dlls/wined3d/resource.c
+++ b/dlls/wined3d/resource.c
@@ -353,7 +353,7 @@ BOOL wined3d_resource_allocate_sysmem(struct wined3d_resource *resource)
     SIZE_T align = RESOURCE_ALIGNMENT - 1 + sizeof(*p);
     void *mem;

-    if (!(mem = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, resource->size + align)))
+    if (!(mem = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, resource->size * 2 + align)))
         return FALSE;

     p = (void **)(((ULONG_PTR)mem + align) & ~(RESOURCE_ALIGNMENT - 1)) - 1;