vb.net - picturebox.Refresh slows down program -

vb.net - picturebox.Refresh slows down program -

g.drawellipse(pen, x, y, 10 + p, 10 + p) g.fillellipse(brushes.red, x, y, 10 + p, 10 + p) picturebox1.refresh()

i using code draw in picturebox. when refresh makes programme extremely slow. have tried invalidate() nil works. works when refresh, slow. drawing 8 circles in picturebox. when utilize picturebox.update() much faster first circle apears? why be?

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