The 160W PSU should be enough for any system with system with IGP and a CPU rated at 95W TDP and below. This gives you room for even a quad-core system. The problem I'd be worrying about is the heat inside the case. I have a 80W mini-ITX system in a really tiny case that's running at 75 C, without any case fans. If I'm doing a system-intensive task, I tend to remove the case cover, and place an electric fan next to the case. This isn't so much to prevent overheating but let the CPU run full speed without being throttled by the CPU's built-in thermal protection.