diff --git a/file.go b/file.go
index 57ac369..4334ff1 100644
--- a/file.go
+++ b/file.go
@@ -16,7 +16,6 @@ import (
 //sys createIoCompletionPort(file syscall.Handle, port syscall.Handle, key uintptr, threadCount uint32) (newport syscall.Handle, err error) = CreateIoCompletionPort
 //sys getQueuedCompletionStatus(port syscall.Handle, bytes *uint32, key *uintptr, o **ioOperation, timeout uint32) (err error) = GetQueuedCompletionStatus
 //sys setFileCompletionNotificationModes(h syscall.Handle, flags uint8) (err error) = SetFileCompletionNotificationModes
-//sys timeBeginPeriod(period uint32) (n int32) = winmm.timeBeginPeriod
 
 type atomicBool int32
 
@@ -153,8 +152,6 @@ func (f *win32File) prepareIo() (*ioOperation, error) {
 
 // ioCompletionProcessor processes completed async IOs forever
 func ioCompletionProcessor(h syscall.Handle) {
-	// Set the timer resolution to 1. This fixes a performance regression in golang 1.6.
-	timeBeginPeriod(1)
 	for {
 		var bytes uint32
 		var key uintptr
diff --git a/zsyscall_windows.go b/zsyscall_windows.go
index 4f7a52e..3f52763 100644
--- a/zsyscall_windows.go
+++ b/zsyscall_windows.go
@@ -38,14 +38,12 @@ func errnoErr(e syscall.Errno) error {
 
 var (
 	modkernel32 = windows.NewLazySystemDLL("kernel32.dll")
-	modwinmm    = windows.NewLazySystemDLL("winmm.dll")
 	modadvapi32 = windows.NewLazySystemDLL("advapi32.dll")
 
 	procCancelIoEx                                           = modkernel32.NewProc("CancelIoEx")
 	procCreateIoCompletionPort                               = modkernel32.NewProc("CreateIoCompletionPort")
 	procGetQueuedCompletionStatus                            = modkernel32.NewProc("GetQueuedCompletionStatus")
 	procSetFileCompletionNotificationModes                   = modkernel32.NewProc("SetFileCompletionNotificationModes")
-	proctimeBeginPeriod                                      = modwinmm.NewProc("timeBeginPeriod")
 	procConnectNamedPipe                                     = modkernel32.NewProc("ConnectNamedPipe")
 	procCreateNamedPipeW                                     = modkernel32.NewProc("CreateNamedPipeW")
 	procCreateFileW                                          = modkernel32.NewProc("CreateFileW")
@@ -122,12 +120,6 @@ func setFileCompletionNotificationModes(h syscall.Handle, flags uint8) (err erro
 	return
 }
 
-func timeBeginPeriod(period uint32) (n int32) {
-	r0, _, _ := syscall.Syscall(proctimeBeginPeriod.Addr(), 1, uintptr(period), 0, 0)
-	n = int32(r0)
-	return
-}
-
 func connectNamedPipe(pipe syscall.Handle, o *syscall.Overlapped) (err error) {
 	r1, _, e1 := syscall.Syscall(procConnectNamedPipe.Addr(), 2, uintptr(pipe), uintptr(unsafe.Pointer(o)), 0)
 	if r1 == 0 {