diff --git a/bench.txt b/bench.txt
new file mode 100644
index 0000000000000000000000000000000000000000..ba8bf45cbfa8cbd3d7b828835e06ca87a31b1fac
--- /dev/null
+++ b/bench.txt
@@ -0,0 +1,9 @@
+go test -benchmem -bench=.
+goos: linux
+goarch: amd64
+pkg: go.jolheiser.com/overlay
+cpu: Intel(R) Core(TM) i7-4700MQ CPU @ 2.40GHz
+BenchmarkCache-8     	134959974	         9.003 ns/op	       0 B/op	       0 allocs/op
+BenchmarkNoCache-8   	  897212	      1369 ns/op	     280 B/op	       4 allocs/op
+PASS
+ok  	go.jolheiser.com/overlay	3.360s
diff --git a/overlay.go b/overlay.go
index 2c14fc35805bfe0b128a2d164e5beaafb71e28f2..512bf1c77ece17e9cc8deba0777e8c8ea60d8e10 100644
--- a/overlay.go
+++ b/overlay.go
@@ -18,17 +18,12 @@ 	doCache bool
 	cache   map[string]bool
 }
 
-// PurgeCache purges the cache
-func (f *FS) PurgeCache() {
-	f.cache = make(map[string]bool)
-}
-
 func (f *FS) apn(name string) string {
 	return path.Join(f.root, name)
 }
 
 func (f *FS) exists(name string) bool {
-	if has, ok := f.cache[name]; ok {
+	if has, ok := f.cache[name]; ok && f.doCache {
 		return has
 	}
 	_, err := os.Stat(f.apn(name))
@@ -68,9 +63,10 @@
 // New returns a new FS
 func New(root string, fs fs.FS, opts ...Option) (*FS, error) {
 	x := &FS{
-		fs:    fs,
+		fs:      fs,
-		root:  root,
+		root:    root,
+		doCache: true,
-		cache: make(map[string]bool),
+		cache:   make(map[string]bool),
 	}
 
 	for _, opt := range opts {