Does it look something like this?
There are a lot of hubs that look like that which are very poor quality.
I bought one to check it out and some of the ports didn't work at all, most were unreliable and some only worked at USB1.1 speeds.
The power supply that came with it was labelled as 5V 1000mA, but couldn't handle more than 4.5V at 200mA or 3.2V at 500mA. I took that apart to check it and it was a very dangerous design with no proper regulation or mains isolation.
If not that one, could you link us to a picture/description of the one you have got?