Temperatures, Cooling and Noise
The HP Envy TouchSmart 4 is a bit thicker than some of the other systems we've recently tested. It's about in-line with the thickness of the ASUS S500C and we would expect temperatures and noise production to be in-line with the ASUS unit as a result.
As you can see, on the front of the system, we logged a maximum temperature of 117 degrees Fahrenheit. This high temperature was located above the keyboard and somewhere you are unlikely to touch during normal use. The keyboard itself saw temperatures of 104 degrees Fahrenheit, which is a bit higher than I'd like to see. It certainly makes gaming uncomfortable as the temperature was observed in between the WSAD keys.
Moving around to the back side, temperatures were even worse. The maximum observed temperature was 130 degrees Fahrenheit. I would not recommend using this system on your lap under any sort of load as temperatures this high can cause permanent discoloration and damage.
The maximum observed GPU temperature was 80 degrees Celsius, which is the same as the CPU because they are on the same die. In this regard, the HP performed much better than the ASUS S500C, but at the cost of external heat.
The Envy TouchSmart 4 produced a sound level of 40 decibels in our measurement, making it one of the quietest machines we have tested. Our measurement is taken in front of the laptop at roughly head level. For comparison, 30dB is a totally quiet night time in the desert, 40dB is whispering and 60dB is a normal conversation.