why wireless are slow?

wireless are slow maybe because of your ISP (Internet Service Provider) they may be limitting your bandwidth and also consider some barriers and level of attenuation of your current location. The more concrete the more your wireless connection will slow..

Well, there can be numerous reasons for it. One, wireless is always slower than wired connection.. it is always far less expensive to wire a connection than a wireless..so your operators are always lagging a generation in wireless as compared to wired connection. Another reason would be the relative positioning of your receiver..may be some concrete somewhere is hampering the signals from reaching you.

Yeah, I agree. This can be due to numerous reasons. It can just be your slow Internet connection speed or too many people sharing the network resulting in slowness of the network. Another possibility would be your own memory space of the processes you are running. They often accumulate themselves over time so you have end some of them after a few hours and restart them.