USB device is very slow

I use Windows SP3 in my PC.
Here hardware are
1.87 GB RAM
AMD Athlon 64×2 Dual Core Processor 6000+ 3.01 Ghz,
HDD 120 GB
The problem is USB device. When I attached any USB drive its always show 'This device can perform faster and its work very slow.
Its too slow to copy any data.
Have you any idea to solve this problem ?
