The folks overseas in Asia always have it better when it comes to smartphones. While the United States offers quad-core smartphones, Asian markets have devices with eight cores! While the new HTC One (M8) does not have an octa-core processor, Asia does still have an advantage with the device. In the United States, the Qualcomm Snapdragon 801 (MSM8974AB) will be clocked at 2.3GHz; however, Asian markets will get the same processor (MSM8974AC) set slightly higher at 2.5GHz.
Just 200MHz separates the two (as well as the end of their IDs). Will the difference between the two devices exist? Yes. Will it be noticeable? I highly doubt it. Regardless, owners of the new HTC One (M8) are getting one hell of a device.