I am not sure what do you mean with the shutdown, but mine never did that. I am playing World of Warcraft and Call Of Duty 4 susing the ATI external video card, and it heats up quite a bit, but never shuts down. Anyway, the heat is not that worrying as it gets heated in the base of the screen and you usually do not touch there.
Think Slim! Business notebooks are usually conservative and rather bulky working devices. Lenovo’s ThinkPad S531 is one alternative that wants to eliminate this prejudice. It combines typical business features with a slim ultrabook design. We checked if the attractive specifications are convincing.