It has the same size and shape as the Teensy 3.6 (2.4 x 0.7 inches) and offers greater I/O capability, Ethernet PHY, SD card socket, and USB host connection. When operating at full load, the Teensy 4.1 requires about 100 mA of power and supports dynamic clock scaling. Unlike traditional microcontrollers, where changing the clock speed can cause incorrect baud rates and other issues, the hardware of the Teensy 4.1 and the software support for the Arduino timing functions from Teensyduino are designed to allow dynamic speed changes without problems. Serial baud rates, audio streaming sample rates, and Arduino functions like delay() and millis(), as well as Teensyduino extensions like IntervalTimer and elapsedMillis, continue to work accurately even when the CPU speed is changed. The Teensy 4.1 also offers a power-off option. By connecting a push button to the On/Off pin, the 3.3V power supply can be completely turned off by holding the button for five seconds and turned back on with a short press. If a coin cell is connected to VBAT, the RTC of the Teensy 4.1 continues to keep track of the date and time even when the power is off. The ARM Cortex-M7 brings many powerful CPU features to a true real-time microcontroller platform. The Cortex-M7 is a dual superscalar processor, meaning the M7 can execute two instructions per clock cycle at 600 MHz. The simultaneous execution of two instructions, of course, depends on the compiler ordering instructions and registers. Initial benchmarks have shown that C++ code compiled by Arduino tends to execute two instructions about 40% to 50% of the time while performing numerically intensive work with integers and pointers. The Cortex-M7 is the first ARM microcontroller to use branch prediction.