Could also be affected by the size of card you have in it. I have the W580i and it's designed for up to 2GB sticks, I've heard that it will still run with a 4GB stick but it slows the phone down a great deal. So if your memory stick is bigger than the phone was designed for, that could slow it down a lot. Other than that, I'd suggest the same as most other people, try to move what you can from the phone's memory onto the memory stick.