Is wired faster than wireless?

Depends what protocol you are using, but lets assume for wireless you're running 802.11g. At this point your max throughput would be 54Mbit/s.
For wired, I'm going to assume100BASE-TX as the most common. At this point you're limited to 100Mbit/s so twice as fast.
But this is max throughput. In real life, you may never even approach 54Mbit/s (how fast is your connection to the outside world? 2Mbit? 4 Mbit? 6??) so it really is irrelevant from this perspective.
Wireless is more prone to interference, but probably not enough to drop your 54Mbit/s to any slower than your internet connection.