The Pixel Watch 3 uses the Qualcomm Snapdragon W5 chipset, which is the same chipset used in the previous Pixel Watch model1. Additionally, it features a custom co-processor, although the specific details of this co-processor have not been specified in the leaked information.
The Pixel Watch 3 display will go up to 2,000 nits of brightness, an improvement from 1,000 nits on the previous model. This increased brightness matches the Apple Watch Series 9 and will make the watch more pleasant to use outside in direct sunlight.
The codenames for the 41 mm and 45 mm Pixel Watch 3 models are selene/helios and luna/sol, respectively. These codenames represent the Bluetooth/WiFi and LTE variants of the smartwatch.