ESP8266 vs ESP32

Specifications	ESP8266	ESP32
MCU	Xtensa Single-core 32-bit L106	Xtensa Dual-Core 32-bit LX6 with 600 DMIPS
802.11 b/g/n Wi-Fi	Yes, HT20	Yes, HT40
WiFi Security	?	WEP, WPA/WPA2 PSK/Enterprise
Hardware Accelerated Encryption	?	AES/SHA2/Elliptical Curve Cryptography/RSA-4096
Bluetooth	None	dual-mode: Bluetooth 4.2 BLE or classi
Typical Frequency	80 MHz	240 MHz
SRAM	160 KB	520 KB
Flash	SPI Flash, up to 16 MB	SPI Flash, up to 16 MB, memory mapped to CPU code space.
GPIO	17	36
Hardware/Software PWM	None/8 channels	1/16 channels
SPI/I2S/I2C/UART	2/1/2/2	3/2/2/3
ADC	10 bit	12-bit, 18 channels
DAC	None	2
CAN	None	?
Ethernet MAC Interface	None	1
Touch Sensor	None	Yes
Temperature Sensor	None	yes
Working Temperature	-40 C - 125 C	-40 C - 125 C
Operating Voltage	?	2.3V to 3.6V C
Power Consumption	77 μA	5 μA power consumption in Deep-sleep

Reference: http://espressif.com/en/products/hardware/esp32/overview