Well first hello here users like me, we will help as we possibly can. To begin, I must tell you that I'm using Galaxy S3 and I can assure you that works for me perfectly, but note that I'm a maniac for updates, that is, I love having my updated to limit device, giving in fact I'm a big gaming and you know perfectly well that the games graphics contribute to slower devices. Remarkably, I used my terminal to the limit by playing, downloading, etc. and I can assure you I will perfect.
But, I have to ask you something ... For starters, what version of Android? Have? baseband version, kernel, etc, if you post your specs here, I can help you better. Also específicame if your terminal is in some company, thank you very much, I'll help you but I need you to tell me that.