Some clarification: I have an external HDD that gets it power from the USB port. Even if I turn of the computer, the HDD won't shut down, because there's power-off charging on that port. This is my only USB3 port, so using an other port is not an option.
Mobil 1 Extended Performance synthetic oil is recommended for oil change intervals up to 15,000 miles or one year, whichever occurs first. However, if your vehicle manufacturer recommends an oil change interval beyond 15,000 miles and Mobil 1 Extended Performance meets the performance level specified, you can be assured that Mobil 1 Extended Performance will go the distance.
I guess I just know too much based on personal experience. Here are my revised oil change recommendations: Change regular petroleum-based oils every 4000 to 5000 miles and synthetic oils every 5000 to 7000 miles.