diff --git a/src/utils/utils.go b/src/utils/utils.go
index 4b48555..f05e24d 100644
--- a/src/utils/utils.go
+++ b/src/utils/utils.go
@@ -186,15 +186,16 @@ func MD5HashFile(fname string, doShowProgress bool) (hash256 []byte, err error)
 	return
 }
 
+var imofull = imohash.NewCustom(0, 0)
+var imopartial = imohash.NewCustom(16*16*8*1024, 128*1024)
+
 // IMOHashFile returns imohash
 func IMOHashFile(fname string) (hash []byte, err error) {
-	b, err := imohash.SumFile(fname)
+	b, err := imopartial.SumFile(fname)
 	hash = b[:]
 	return
 }
 
-var imofull = imohash.NewCustom(0, 0)
-
 // IMOHashFileFull returns imohash of full file
 func IMOHashFileFull(fname string) (hash []byte, err error) {
 	b, err := imofull.SumFile(fname)
diff --git a/src/utils/utils_test.go b/src/utils/utils_test.go
index a479189..a309422 100644
--- a/src/utils/utils_test.go
+++ b/src/utils/utils_test.go
@@ -108,7 +108,7 @@ func TestIMOHashFile(t *testing.T) {
 	defer os.Remove("bigfile.test")
 	b, err := IMOHashFile("bigfile.test")
 	assert.Nil(t, err)
-	assert.Equal(t, "c0d1e123ca94148ffea146137684ebb9", fmt.Sprintf("%x", b))
+	assert.Equal(t, "c0d1e12301e6c635f6d4a8ea5c897437", fmt.Sprintf("%x", b))
 }
 
 func TestXXHashFile(t *testing.T) {