Hello, brand new MBP here and am loving it. One minor gripe is that it runs warm to the touch on the bottom and am wondering if this is normal? Just have skype, safari with a few tabs and messages running.
Perfectly normal as explained by snaky69.
Since the laptop enclosure is made of aluminum and acts as a large heat sink, it is normal for the enclose to become hot closest to the heat source. The 15-inch Retina MacBook Pro includes a single CPU/iGPU chip but may also include a separate dGPU chip. These processors are located below the back center edge of the keyboard. Two large cooling fans below the side edges of the keyboard connect to heat pips that transfer heat from the processors to the fans. That is the basic heat footprint and where you should expect the enclosure to feel the hottest. However, if you have the laptop plugged in to external power and it is charging your battery, or if you have a Thunderbolt connection with a large amount of data transfer then that can also generate a significant amount of heat near the cable connections. If you want to see the layout of laptop components then you can checkout iFixit://
www.ifixit.com/Device/Mac_Laptop
Something else to keep in mind is that there can be a significant amount of background activities occurring, which can contribute to increased temperatures, and this is especially true for a new computer. To track these activities you can run Apple Activity Monitor.
https://support.apple.com/en-us/HT201464
For instance Apple Spotlight, Apple Diagnostic Reporting, Apple Time Machine, DropBox, other icloud storage systems can increase temperatures.
https://support.apple.com/en-us/HT203447
https://support.apple.com/kb/PH18763?viewlocale=en_US&locale=en_US
If you want to look at component temperatures then HWSensors is free but does not provide fan speed control, while iStat Menus offers fan speed control and a free trial. Just keep in mind that temps jump all over the place so you can only get an accurate understanding of temperatures by using averages over a set period of time and equal conditions.
http://www.hwsensors.com
http://bjango.com/mac/istatmenus/
Checkout Intel’s free Power Gadget application so that you can accurately monitor CPU temps, CPU power and CPU speeds with the data logging function. This is one of the best ways to see what is really going on because most real time monitors jump all over the place so it become impossible to get a good sense of temperatures and whether your machining is throttling. It is what I use for performance testing.
https://software.intel.com/en-us/articles/intel-power-gadget-20