diff --git a/dlls/user32/clipboard.c b/dlls/user32/clipboard.c
index 9a7753520f5..7e5a3e0b022 100644
--- a/dlls/user32/clipboard.c
+++ b/dlls/user32/clipboard.c
@@ -48,17 +48,6 @@
 WINE_DEFAULT_DEBUG_CHANNEL(clipboard);
 
 
-struct cached_format
-{
-    struct list entry;       /* entry in cache list */
-    UINT        format;      /* format id */
-    UINT        seqno;       /* sequence number when the data was set */
-    HANDLE      handle;      /* original data handle */
-};
-
-static struct list cached_formats = LIST_INIT( cached_formats );
-static struct list formats_to_free = LIST_INIT( formats_to_free );
-
 static CRITICAL_SECTION clipboard_cs;
 static CRITICAL_SECTION_DEBUG critsect_debug =
 {
@@ -119,7 +108,7 @@ static const char *debugstr_format( UINT id )
 }
 
 /* build the data to send to the server in SetClipboardData */
-static HANDLE marshal_data( UINT format, HANDLE handle, data_size_t *ret_size )
+static HANDLE marshal_data( UINT format, HANDLE handle, size_t *ret_size )
 {
     SIZE_T size;
 
@@ -258,110 +247,35 @@ static HANDLE unmarshal_data( UINT format, void *data, data_size_t size )
     return handle;
 }
 
-/* retrieve a data format from the cache */
-static struct cached_format *get_cached_format( UINT format )
-{
-    struct cached_format *cache;
-
-    LIST_FOR_EACH_ENTRY( cache, &cached_formats, struct cached_format, entry )
-        if (cache->format == format) return cache;
-    return NULL;
-}
-
-/* store data in the cache, or reuse the existing one if available */
-static HANDLE cache_data( UINT format, HANDLE data, data_size_t size, UINT seqno,
-                          struct cached_format *cache )
-{
-    if (cache)
-    {
-        if (seqno == cache->seqno)  /* we can reuse the cached data */
-        {
-            GlobalFree( data );
-            return cache->handle;
-        }
-        /* cache entry is stale, remove it */
-        list_remove( &cache->entry );
-        list_add_tail( &formats_to_free, &cache->entry );
-    }
-
-    /* allocate new cache entry */
-    if (!(cache = HeapAlloc( GetProcessHeap(), 0, sizeof(*cache) )))
-    {
-        GlobalFree( data );
-        return 0;
-    }
-    cache->format = format;
-    cache->seqno  = seqno;
-    cache->handle = unmarshal_data( format, data, size );
-    list_add_tail( &cached_formats, &cache->entry );
-    return cache->handle;
-}
-
 /* free a single cached format */
-static void free_cached_data( struct cached_format *cache )
+void free_cached_data( UINT format, HANDLE handle )
 {
     void *ptr;
 
-    switch (cache->format)
+    switch (format)
     {
     case CF_BITMAP:
     case CF_DSPBITMAP:
     case CF_PALETTE:
-        DeleteObject( cache->handle );
+        DeleteObject( handle );
         break;
     case CF_ENHMETAFILE:
     case CF_DSPENHMETAFILE:
-        DeleteEnhMetaFile( cache->handle );
+        DeleteEnhMetaFile( handle );
         break;
     case CF_METAFILEPICT:
     case CF_DSPMETAFILEPICT:
-        if ((ptr = GlobalLock( cache->handle )))
+        if ((ptr = GlobalLock( handle )))
         {
             DeleteMetaFile( ((METAFILEPICT *)ptr)->hMF );
-            GlobalUnlock( cache->handle );
+            GlobalUnlock( handle );
         }
-        GlobalFree( cache->handle );
+        GlobalFree( handle );
         break;
     default:
-        GlobalFree( cache->handle );
+        GlobalFree( handle );
         break;
     }
-    list_remove( &cache->entry );
-    HeapFree( GetProcessHeap(), 0, cache );
-}
-
-/* clear global memory formats; special types are freed on EmptyClipboard */
-static void invalidate_memory_formats(void)
-{
-    struct cached_format *cache, *next;
-
-    LIST_FOR_EACH_ENTRY_SAFE( cache, next, &cached_formats, struct cached_format, entry )
-    {
-        switch (cache->format)
-        {
-        case CF_BITMAP:
-        case CF_DSPBITMAP:
-        case CF_PALETTE:
-        case CF_ENHMETAFILE:
-        case CF_DSPENHMETAFILE:
-        case CF_METAFILEPICT:
-        case CF_DSPMETAFILEPICT:
-            continue;
-        default:
-            free_cached_data( cache );
-            break;
-        }
-    }
-}
-
-/* free all the data in the cache */
-static void free_cached_formats(void)
-{
-    struct list *ptr;
-
-    list_move_tail( &formats_to_free, &cached_formats );
-    while ((ptr = list_head( &formats_to_free )))
-        free_cached_data( LIST_ENTRY( ptr, struct cached_format, entry ));
 }
 
 /* get the clipboard locale stored in the CF_LOCALE format */
@@ -576,7 +490,7 @@ static HANDLE render_synthesized_enhmetafile( HANDLE data )
 }
 
 /* render a synthesized format */
-static HANDLE render_synthesized_format( UINT format, UINT from )
+HANDLE render_synthesized_format( UINT format, UINT from )
 {
     HANDLE data = GetClipboardData( from );
 
@@ -650,55 +564,7 @@ INT WINAPI GetClipboardFormatNameA( UINT format, LPSTR buffer, INT maxlen )
  */
 BOOL WINAPI OpenClipboard( HWND hwnd )
 {
-    BOOL ret;
-    HWND owner;
-
-    TRACE( "%p\n", hwnd );
-
-    NtUserCallNoParam( NtUserUpdateClipboard );
-
-    EnterCriticalSection( &clipboard_cs );
-
-    SERVER_START_REQ( open_clipboard )
-    {
-        req->window = wine_server_user_handle( hwnd );
-        ret = !wine_server_call_err( req );
-        owner = wine_server_ptr_handle( reply->owner );
-    }
-    SERVER_END_REQ;
-
-    if (ret && !WIN_IsCurrentProcess( owner )) invalidate_memory_formats();
-
-    LeaveCriticalSection( &clipboard_cs );
-    return ret;
-}
-
-
-/**************************************************************************
- *		EmptyClipboard (USER32.@)
- * Empties and acquires ownership of the clipboard
- */
-BOOL WINAPI EmptyClipboard(void)
-{
-    BOOL ret;
-    HWND owner = NtUserGetClipboardOwner();
-
-    TRACE( "owner %p\n", owner );
-
-    if (owner) SendMessageTimeoutW( owner, WM_DESTROYCLIPBOARD, 0, 0, SMTO_ABORTIFHUNG, 5000, NULL );
-
-    EnterCriticalSection( &clipboard_cs );
-
-    SERVER_START_REQ( empty_clipboard )
-    {
-        ret = !wine_server_call_err( req );
-    }
-    SERVER_END_REQ;
-
-    if (ret) free_cached_formats();
-
-    LeaveCriticalSection( &clipboard_cs );
-    return ret;
+    return NtUserOpenClipboard( hwnd, 0 );
 }
 
 
@@ -707,55 +573,28 @@ BOOL WINAPI EmptyClipboard(void)
  */
 HANDLE WINAPI SetClipboardData( UINT format, HANDLE data )
 {
-    struct cached_format *cache = NULL;
-    void *ptr = NULL;
-    data_size_t size = 0;
-    HANDLE handle = data, retval = 0;
-    NTSTATUS status = STATUS_SUCCESS;
+    struct set_clipboard_params params = { .size = 0 };
+    HANDLE handle = data;
+    NTSTATUS status;
 
     TRACE( "%s %p\n", debugstr_format( format ), data );
 
     if (data)
     {
-        if (!(handle = marshal_data( format, data, &size ))) return 0;
-        if (!(ptr = GlobalLock( handle ))) goto done;
-        if (!(cache = HeapAlloc( GetProcessHeap(), 0, sizeof(*cache) ))) goto done;
-        cache->format = format;
-        cache->handle = data;
+        if (!(handle = marshal_data( format, data, &params.size ))) return 0;
+        if (!(params.data = GlobalLock( handle ))) return 0;
     }
 
-    EnterCriticalSection( &clipboard_cs );
+    status = NtUserSetClipboardData( format, data, &params );
 
-    SERVER_START_REQ( set_clipboard_data )
-    {
-        req->format = format;
-        req->lcid = GetUserDefaultLCID();
-        wine_server_add_data( req, ptr, size );
-        if (!(status = wine_server_call( req )))
-        {
-            if (cache) cache->seqno = reply->seqno;
-        }
-    }
-    SERVER_END_REQ;
-
-    if (!status)
-    {
-        /* free the previous entry if any */
-        struct cached_format *prev;
-
-        if ((prev = get_cached_format( format ))) free_cached_data( prev );
-        if (cache) list_add_tail( &cached_formats, &cache->entry );
-        retval = data;
-    }
-    else HeapFree( GetProcessHeap(), 0, cache );
-
-    LeaveCriticalSection( &clipboard_cs );
-
-done:
-    if (ptr) GlobalUnlock( handle );
+    if (params.data) GlobalUnlock( handle );
     if (handle != data) GlobalFree( handle );
-    if (status) SetLastError( RtlNtStatusToDosError( status ));
-    return retval;
+    if (status)
+    {
+        SetLastError( RtlNtStatusToDosError( status ));
+        return 0;
+    }
+    return data;
 }
 
 
@@ -773,73 +612,34 @@ UINT WINAPI EnumClipboardFormats( UINT format )
  */
 HANDLE WINAPI GetClipboardData( UINT format )
 {
-    struct cached_format *cache;
-    NTSTATUS status;
-    UINT from, data_seqno;
-    HWND owner;
-    HANDLE data;
-    UINT size = 1024;
-    BOOL render = TRUE;
+    struct get_clipboard_params params = { .data_size = 1024 };
+    HANDLE ret = 0;
 
-    for (;;)
+    EnterCriticalSection( &clipboard_cs );
+
+    while (params.data_size)
     {
-        if (!(data = GlobalAlloc( GMEM_FIXED, size ))) return 0;
-
-        EnterCriticalSection( &clipboard_cs );
-        cache = get_cached_format( format );
-
-        SERVER_START_REQ( get_clipboard_data )
+        params.size = params.data_size;
+        params.data_size = 0;
+        if (!(params.data = GlobalAlloc( GMEM_FIXED, params.size ))) break;
+        ret = NtUserGetClipboardData( format, &params );
+        if (ret) break;
+        if (params.data_size == ~0) /* needs unmarshaling */
         {
-            req->format = format;
-            req->render = render;
-            if (cache)
-            {
-                req->cached = 1;
-                req->seqno = cache->seqno;
-            }
-            wine_server_set_reply( req, data, size );
-            status = wine_server_call( req );
-            from = reply->from;
-            size = reply->total;
-            data_seqno = reply->seqno;
-            owner = wine_server_ptr_handle( reply->owner );
-        }
-        SERVER_END_REQ;
+            struct set_clipboard_params set_params = { .cache_only = TRUE, .seqno = params.seqno };
 
-        if (!status && size)
-        {
-            data = cache_data( format, data, size, data_seqno, cache );
-            LeaveCriticalSection( &clipboard_cs );
-            TRACE( "%s returning %p\n", debugstr_format( format ), data );
-            return data;
-        }
-        LeaveCriticalSection( &clipboard_cs );
-        GlobalFree( data );
+            ret = unmarshal_data( format, params.data, params.size );
+            if (!NtUserSetClipboardData( format, ret, &set_params )) break;
 
-        if (status == STATUS_BUFFER_OVERFLOW) continue;  /* retry with the new size */
-        if (status == STATUS_OBJECT_NAME_NOT_FOUND) return 0; /* no such format */
-        if (status)
-        {
-            SetLastError( RtlNtStatusToDosError( status ));
-            TRACE( "%s error %08x\n", debugstr_format( format ), status );
-            return 0;
+            /* data changed, retry */
+            free_cached_data( format, ret );
+            ret = 0;
+            params.data_size = 1024;
+            continue;
         }
-        if (render)  /* try rendering it */
-        {
-            render = FALSE;
-            if (from)
-            {
-                render_synthesized_format( format, from );
-                continue;
-            }
-            else if (owner)
-            {
-                TRACE( "%s sending WM_RENDERFORMAT to %p\n", debugstr_format( format ), owner );
-                SendMessageW( owner, WM_RENDERFORMAT, format, 0 );
-                continue;
-            }
-        }
-        TRACE( "%s returning 0\n", debugstr_format( format ));
-        return 0;
+        GlobalFree( params.data );
     }
+
+    LeaveCriticalSection( &clipboard_cs );
+    return ret;
 }
diff --git a/dlls/user32/edit.c b/dlls/user32/edit.c
index 242ef4abeb2..f15c4c8e550 100644
--- a/dlls/user32/edit.c
+++ b/dlls/user32/edit.c
@@ -3134,7 +3134,7 @@ static void EDIT_WM_Copy(EDITSTATE *es)
 	TRACE("%s\n", debugstr_w(dst));
 	GlobalUnlock(hdst);
 	OpenClipboard(es->hwndSelf);
-	EmptyClipboard();
+	NtUserEmptyClipboard();
 	SetClipboardData(CF_UNICODETEXT, hdst);
 	NtUserCloseClipboard();
 }
diff --git a/dlls/user32/user32.spec b/dlls/user32/user32.spec
index a7b2f7e0681..ec078cc7609 100644
--- a/dlls/user32/user32.spec
+++ b/dlls/user32/user32.spec
@@ -202,7 +202,7 @@
 @ stdcall DrawTextExW(long wstr long ptr long ptr)
 @ stdcall DrawTextW(long wstr long ptr long)
 @ stdcall EditWndProc(long long long long) EditWndProcA
-@ stdcall EmptyClipboard()
+@ stdcall EmptyClipboard() NtUserEmptyClipboard
 @ stdcall EnableMenuItem(long long long) NtUserEnableMenuItem
 @ stdcall EnableMouseInPointer(long)
 @ stdcall EnableNonClientDpiScaling(long)
diff --git a/dlls/user32/user_main.c b/dlls/user32/user_main.c
index 08f2833ee3f..85e22525d80 100644
--- a/dlls/user32/user_main.c
+++ b/dlls/user32/user_main.c
@@ -184,6 +184,20 @@ static const struct user_callbacks user_funcs =
     unregister_imm,
 };
 
+static NTSTATUS WINAPI User32FreeCachedClipboardData( const struct free_cached_data_params *params,
+                                                      ULONG size )
+{
+    free_cached_data( params->format, params->handle );
+    return 0;
+}
+
+static NTSTATUS WINAPI User32RenderSsynthesizedFormat( const struct render_synthesized_format_params *params,
+                                                       ULONG size )
+{
+    render_synthesized_format( params->format, params->from );
+    return 0;
+}
+
 static BOOL WINAPI User32LoadDriver( const WCHAR *path, ULONG size )
 {
     return LoadLibraryW( path ) != NULL;
@@ -196,7 +210,9 @@ static const void *kernel_callback_table[NtUserCallCount] =
     User32CallWinEventHook,
     User32CallWindowProc,
     User32CallWindowsHook,
+    User32FreeCachedClipboardData,
     User32LoadDriver,
+    User32RenderSsynthesizedFormat,
 };
 
 
diff --git a/dlls/user32/user_private.h b/dlls/user32/user_private.h
index 54b11f2a8ef..b01c5b8bfda 100644
--- a/dlls/user32/user_private.h
+++ b/dlls/user32/user_private.h
@@ -82,6 +82,8 @@ extern BOOL process_rawinput_message( MSG *msg, UINT hw_id,
                                       const struct hardware_msg_data *msg_data ) DECLSPEC_HIDDEN;
 extern BOOL unpack_dde_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lparam,
                                 void **buffer, size_t size ) DECLSPEC_HIDDEN;
+extern void free_cached_data( UINT format, HANDLE handle ) DECLSPEC_HIDDEN;
+extern HANDLE render_synthesized_format( UINT format, UINT from ) DECLSPEC_HIDDEN;
 
 extern void CLIPBOARD_ReleaseOwner( HWND hwnd ) DECLSPEC_HIDDEN;
 extern BOOL FOCUS_MouseActivate( HWND hwnd ) DECLSPEC_HIDDEN;
diff --git a/dlls/win32u/clipboard.c b/dlls/win32u/clipboard.c
index d338f27dcc8..63306702b1c 100644
--- a/dlls/win32u/clipboard.c
+++ b/dlls/win32u/clipboard.c
@@ -27,6 +27,9 @@
 #pragma makedep unix
 #endif
 
+#include <pthread.h>
+#include "ntstatus.h"
+#define WIN32_NO_STATUS
 #include "win32u_private.h"
 #include "ntuser_private.h"
 #include "wine/server.h"
@@ -34,6 +37,19 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(clipboard);
 
+static pthread_mutex_t clipboard_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+struct cached_format
+{
+    struct list entry;       /* entry in cache list */
+    UINT        format;      /* format id */
+    UINT        seqno;       /* sequence number when the data was set */
+    HANDLE      handle;      /* original data handle */
+};
+
+static struct list cached_formats = LIST_INIT( cached_formats );
+static struct list formats_to_free = LIST_INIT( formats_to_free );
+
 
 /* get a debug string for a format id */
 static const char *debugstr_format( UINT id )
@@ -76,13 +92,106 @@ static const char *debugstr_format( UINT id )
     }
 }
 
+/* retrieve a data format from the cache */
+static struct cached_format *get_cached_format( UINT format )
+{
+    struct cached_format *cache;
+
+    LIST_FOR_EACH_ENTRY( cache, &cached_formats, struct cached_format, entry )
+        if (cache->format == format) return cache;
+    return NULL;
+}
+
+/* free a single cached format */
+static void free_cached_data( struct cached_format *cache )
+{
+    struct free_cached_data_params params;
+    void *ret_ptr;
+    ULONG ret_len;
+
+    switch (cache->format)
+    {
+    case CF_BITMAP:
+    case CF_DSPBITMAP:
+    case CF_PALETTE:
+        NtGdiDeleteObjectApp( cache->handle );
+        break;
+
+    default:
+        params.format = cache->format;
+        params.handle = cache->handle;
+        KeUserModeCallback( NtUserFreeCachedClipboardData, &params, sizeof(params),
+                            &ret_ptr, &ret_len );
+        break;
+    }
+    free( cache );
+}
+
+/* free all the data in the cache */
+static void free_cached_formats( struct list *list )
+{
+    struct list *ptr;
+
+    while ((ptr = list_head( list )))
+    {
+        list_remove( ptr );
+        free_cached_data( LIST_ENTRY( ptr, struct cached_format, entry ));
+    }
+}
+
+/* clear global memory formats; special types are freed on EmptyClipboard */
+static void invalidate_memory_formats( struct list *free_list )
+{
+    struct cached_format *cache, *next;
+
+    LIST_FOR_EACH_ENTRY_SAFE( cache, next, &cached_formats, struct cached_format, entry )
+    {
+        switch (cache->format)
+        {
+        case CF_BITMAP:
+        case CF_DSPBITMAP:
+        case CF_PALETTE:
+        case CF_ENHMETAFILE:
+        case CF_DSPENHMETAFILE:
+        case CF_METAFILEPICT:
+        case CF_DSPMETAFILEPICT:
+            continue;
+        default:
+            list_remove( &cache->entry );
+            list_add_tail( free_list, &cache->entry );
+            break;
+        }
+    }
+}
+
 /**************************************************************************
  *           NtUserOpenClipboard    (win32u.@)
  */
 BOOL WINAPI NtUserOpenClipboard( HWND hwnd, ULONG unk )
 {
-    FIXME( "\n" );
-    return FALSE;
+    struct list free_list = LIST_INIT( free_list );
+    BOOL ret;
+    HWND owner;
+
+    TRACE( "%p\n", hwnd );
+
+    user_driver->pUpdateClipboard();
+
+    pthread_mutex_lock( &clipboard_mutex );
+
+    SERVER_START_REQ( open_clipboard )
+    {
+        req->window = wine_server_user_handle( hwnd );
+        ret = !wine_server_call_err( req );
+        owner = wine_server_ptr_handle( reply->owner );
+    }
+    SERVER_END_REQ;
+
+    if (ret && !is_current_process_window( owner )) invalidate_memory_formats( &free_list );
+
+    pthread_mutex_unlock( &clipboard_mutex );
+    free_cached_formats( &free_list );
+    return ret;
 }
 
 /**************************************************************************
@@ -115,8 +224,32 @@ BOOL WINAPI NtUserCloseClipboard(void)
  */
 BOOL WINAPI NtUserEmptyClipboard(void)
 {
-    FIXME( "\n" );
-    return FALSE;
+    BOOL ret;
+    HWND owner = NtUserGetClipboardOwner();
+    struct list free_list = LIST_INIT( free_list );
+
+    TRACE( "owner %p\n", owner );
+
+    if (owner) send_message_timeout( owner, WM_DESTROYCLIPBOARD, 0, 0, SMTO_ABORTIFHUNG,
+                                     5000, NULL, FALSE );
+
+    pthread_mutex_lock( &clipboard_mutex );
+
+    SERVER_START_REQ( empty_clipboard )
+    {
+        ret = !wine_server_call_err( req );
+    }
+    SERVER_END_REQ;
+
+    if (ret)
+    {
+        list_move_tail( &free_list, &formats_to_free );
+        list_move_tail( &free_list, &cached_formats );
+    }
+
+    pthread_mutex_unlock( &clipboard_mutex );
+    free_cached_formats( &free_list );
+    return ret;
 }
 
 /**************************************************************************
@@ -432,10 +565,65 @@ void release_clipboard_owner( HWND hwnd )
 /**************************************************************************
  *           NtUserSetClipboardData    (win32u.@)
  */
-NTSTATUS WINAPI NtUserSetClipboardData( UINT format, HANDLE handle, struct set_clipboard_params *params )
+NTSTATUS WINAPI NtUserSetClipboardData( UINT format, HANDLE data, struct set_clipboard_params *params )
 {
-    FIXME( "\n" );
-    return 0;
+    struct cached_format *cache = NULL, *prev = NULL;
+    void *ptr = NULL;
+    data_size_t size = 0;
+    NTSTATUS status = STATUS_SUCCESS;
+
+    TRACE( "%s %p\n", debugstr_format( format ), data );
+
+    if (params->cache_only)
+    {
+        pthread_mutex_lock( &clipboard_mutex );
+        if ((cache = get_cached_format( format )) && cache->seqno == params->seqno)
+            cache->handle = data;
+        else
+            status = STATUS_UNSUCCESSFUL;
+        pthread_mutex_unlock( &clipboard_mutex );
+        return status;
+    }
+
+    if (params->data)
+    {
+        ptr = params->data;
+        size = params->size;
+        if (data)
+        {
+            if (!(cache = malloc( sizeof(*cache) ))) goto done;
+            cache->format = format;
+            cache->handle = data;
+        }
+    }
+
+    pthread_mutex_lock( &clipboard_mutex );
+
+    SERVER_START_REQ( set_clipboard_data )
+    {
+        req->format = format;
+        NtQueryDefaultLocale( TRUE, &req->lcid );
+        wine_server_add_data( req, ptr, size );
+        if (!(status = wine_server_call( req )))
+        {
+            if (cache) cache->seqno = reply->seqno;
+        }
+    }
+    SERVER_END_REQ;
+
+    if (!status)
+    {
+        /* free the previous entry if any */
+        if ((prev = get_cached_format( format ))) list_remove( &prev->entry );
+        if (cache) list_add_tail( &cached_formats, &cache->entry );
+    }
+    else free( cache );
+
+    pthread_mutex_unlock( &clipboard_mutex );
+    if (prev) free_cached_data( prev );
+
+done:
+    return status;
 }
 
 /**************************************************************************
@@ -443,6 +631,102 @@ NTSTATUS WINAPI NtUserSetClipboardData( UINT format, HANDLE handle, struct set_c
  */
 HANDLE WINAPI NtUserGetClipboardData( UINT format, struct get_clipboard_params *params )
 {
-    FIXME( "\n" );
-    return 0;
+    struct cached_format *cache;
+    NTSTATUS status;
+    UINT from, data_seqno;
+    size_t size;
+    HWND owner;
+    BOOL render = TRUE;
+
+    for (;;)
+    {
+        pthread_mutex_lock( &clipboard_mutex );
+
+        cache = get_cached_format( format );
+
+        SERVER_START_REQ( get_clipboard_data )
+        {
+            req->format = format;
+            req->render = render;
+            if (cache && cache->handle)
+            {
+                req->cached = 1;
+                req->seqno = cache->seqno;
+            }
+            wine_server_set_reply( req, params->data, params->size );
+            status = wine_server_call( req );
+            from = reply->from;
+            size = reply->total;
+            data_seqno = reply->seqno;
+            owner = wine_server_ptr_handle( reply->owner );
+        }
+        SERVER_END_REQ;
+
+        if (!status && size)
+        {
+            if (cache)
+            {
+                if (cache->handle && data_seqno == cache->seqno)  /* we can reuse the cached data */
+                {
+                    HANDLE ret = cache->handle;
+                    pthread_mutex_unlock( &clipboard_mutex );
+                    TRACE( "%s returning %p\n", debugstr_format( format ), ret );
+                    return ret;
+                }
+
+                /* cache entry is stale, remove it */
+                list_remove( &cache->entry );
+                list_add_tail( &formats_to_free, &cache->entry );
+            }
+
+            /* allocate new cache entry */
+            if (!(cache = malloc( sizeof(*cache) ))) return 0;
+
+            cache->format = format;
+            cache->seqno  = data_seqno;
+            cache->handle = NULL;
+            params->seqno = cache->seqno;
+            list_add_tail( &cached_formats, &cache->entry );
+            pthread_mutex_unlock( &clipboard_mutex );
+            TRACE( "%s needs unmarshaling\n", debugstr_format( format ) );
+            params->data_size = ~0;
+            params->size = size;
+            return 0;
+        }
+        pthread_mutex_unlock( &clipboard_mutex );
+
+        if (status == STATUS_BUFFER_OVERFLOW)
+        {
+            params->data_size = size;
+            return 0;
+        }
+        if (status == STATUS_OBJECT_NAME_NOT_FOUND) return 0; /* no such format */
+        if (status)
+        {
+            SetLastError( RtlNtStatusToDosError( status ));
+            TRACE( "%s error %08x\n", debugstr_format( format ), status );
+            return 0;
+        }
+        if (render)  /* try rendering it */
+        {
+            render = FALSE;
+            if (from)
+            {
+                struct render_synthesized_format_params params = { .format = format, .from = from };
+                ULONG ret_len;
+                void *ret_ptr;
+                KeUserModeCallback( NtUserRenderSynthesizedFormat, &params, sizeof(params),
+                                    &ret_ptr, &ret_len );
+                continue;
+            }
+            if (owner)
+            {
+                TRACE( "%s sending WM_RENDERFORMAT to %p\n", debugstr_format( format ), owner );
+                send_message( owner, WM_RENDERFORMAT, format, 0 );
+                continue;
+            }
+        }
+        TRACE( "%s returning 0\n", debugstr_format( format ));
+        return 0;
+    }
 }
diff --git a/dlls/win32u/sysparams.c b/dlls/win32u/sysparams.c
index 3b380c017e5..6ec92552df1 100644
--- a/dlls/win32u/sysparams.c
+++ b/dlls/win32u/sysparams.c
@@ -4671,10 +4671,6 @@ ULONG_PTR WINAPI NtUserCallNoParam( ULONG code )
         thread_detach();
         return 0;
 
-    case NtUserUpdateClipboard:
-        user_driver->pUpdateClipboard();
-        return 0;
-
     default:
         FIXME( "invalid code %u\n", code );
         return 0;
diff --git a/include/ntuser.h b/include/ntuser.h
index 75c44372f24..0a833d467b3 100644
--- a/include/ntuser.h
+++ b/include/ntuser.h
@@ -32,7 +32,9 @@ enum
     NtUserCallWinEventHook,
     NtUserCallWinProc,
     NtUserCallWindowsHook,
+    NtUserFreeCachedClipboardData,
     NtUserLoadDriver,
+    NtUserRenderSynthesizedFormat,
     /* win16 hooks */
     NtUserCallFreeIcon,
     NtUserThunkLock,
@@ -140,6 +142,20 @@ struct win_hook_params
     WCHAR module[MAX_PATH];
 };
 
+/* NtUserFreeCachedClipboardData params */
+struct free_cached_data_params
+{
+    UINT format;
+    HANDLE handle;
+};
+
+/* NtUserRenderSynthesizedFormat params */
+struct render_synthesized_format_params
+{
+    UINT format;
+    UINT from;
+};
+
 /* process DPI awareness contexts */
 #define NTUSER_DPI_UNAWARE                0x00006010
 #define NTUSER_DPI_SYSTEM_AWARE           0x00006011
@@ -237,11 +253,19 @@ struct client_menu_name
 /* NtUserGetClipboardData params, not compatible with Windows */
 struct get_clipboard_params
 {
+    void  *data;
+    size_t size;
+    size_t data_size;
+    UINT   seqno;
 };
 
 /* NtUserSetClipboardData params, not compatible with Windows */
 struct set_clipboard_params
 {
+    void  *data;
+    size_t size;
+    BOOL   cache_only;
+    UINT   seqno;
 };
 
 /* internal messages codes */
@@ -624,7 +648,6 @@ enum
     /* temporary exports */
     NtUserExitingThread,
     NtUserThreadDetach,
-    NtUserUpdateClipboard,
 };
 
 static inline HWND NtUserGetDesktopWindow(void)