how to draw circles faster

Hi,

I'm trying to make the MS Windows version of my program draw circles faster.  
Right now, GDK (I'm using GTK+1.3.0-20030216) only has gdk_draw_arc, which 
can only draw one circle at a time.  On UNIX machines, XLib has XDrawArcs,
which can draw multiple circles at a time and is more efficient than 
XDrawArc called repeatedly.  Is there any counterpart of XDrawArcs in MS
Windows GDI?  Googling for "Arcs" did not get me anything useful.
Any suggestions will be greatly appreciated.

Best wishes,

C h i s h e n g   H u a n g

PS. As a side note, I used gdk_win32_draw_arc in gdk/win32/gdkdrawable-win32.c 
    as a starting point and hacked up a function that did the followings:
      1. Calling gdk_gc_predraw in the beginning,
      2. Calling Arc for each circle center and diameter,
      3. Calling gdk_gc_postdraw in the end.
    This only helped a little bit (~6% speedup).