ATI Mobility Radeon HD 4570 512MB VRAM and ATI Radeon HD 3200 Graphics which one is better for gaming??????

The ATI Radeon HD 3200 is integrated (I have it). I can play games like Left 4 Dead but only with a low resolution and lowest settings, so it stinks. The 4570 sounds like is has dedicated memory, and with 512MB, it is by far the better choice.