Why is my model flickering when translating

I have several models here. When they stand still during gameTime, there's no flickering. But as soon as I move them across the x-axis, they flicker on some places.

protected override void Draw(GameTime gameTime)
{
    graphics.GraphicsDevice.Clear(Color.CornflowerBlue);

    Matrix[] transforms = new Matrix[myModel.Bones.Count];
    myModel.CopyAbsoluteBoneTransformsTo(transforms);

    foreach (ModelMesh mesh in myModel.Meshes)
    {
        foreach (BasicEffect effect in mesh.Effects)
        {
            effect.EnableDefaultLighting();
            effect.World = transforms[mesh.ParentBone.Index] * 
                Matrix.CreateRotationY(modelRotation)
                * Matrix.CreateTranslation(modelPosition);
            effect.View = Matrix.CreateLookAt(cameraPosition, 
                Vector3.Zero, Vector3.Up);
            effect.Projection = Matrix.CreatePerspectiveFieldOfView(
                MathHelper.ToRadians(45.0f), aspectRatio, 
                1.0f, 10000.0f);
        }
        mesh.Draw();
    }
    base.Draw(gameTime);
}

Why is that happening and what could I do to prevent it?