It doesn't directly mean it will be faster. You need to compare phone specs. Do research online and check stuff like the processor speed, RAM, etc. If you use Bluetooth for tethering (this usually requires third party software if i'm not mistaken), then find which of the phones is using Bluetooth 2.0 or 3.0 (3.0 is better). If you use a USB cable, USB 2.0 ports are faster than USB 1.0 (if your PC has USB 3.0 ports, then its even better) ports.
Finally, when in the act of thethering, you should also know that if the phone is running some demanding app or something already, it reduces the resources left for handling the communication of your PC with the internet through the phone's mobile network