With the TES 1326 Infrared Thermometer literally in hand we found ourselves getting real-world temperatures from the products we test at load (3D clock speeds).
There are two places we pull temperature from - the back of the card directly behind the core and if the card is dual slot and has an exhaust point we also pull a temperate from there, as seen in the picture.
Even though the HD 5770 is a faster card, the extra heat coming off the back of the core is only minor thanks to the great cooling option.
Pulling out the TES 1350A Sound Level Meter we find ourselves quickly yelling into the top of it to see how loud we can be.
After five minutes of that we get a bit more serious and place the device two CM away from the fan on the card to find the maximum noise level of the card when idle (2D mode) and in load (3D mode).
While both cards use the same cooler, the HD 5770 managed to run a fair bit quieter than the HD 5750.