I am using a data card (Micromax MMX 353 G). This data card operates finely in my laptop while it operates slowly in my desktop PC. I mean the internet speed remains same, but the browsers and data card interface software operate very slowly in desktop than laptop. Now the hard disk in my desktop is 75 GB and RAM is 1 GB while in laptop it is 300 GB and 4GB respectively. D and E drives of hard disk in my desktop are more than half filled by movies while C is obviously reserved for program files. I wonder if lack of memory in hard disk and RAM is making data card operate slower in desktop.

Where do you plug it in on the desktop? I ask because there is usually a difference between the front case USB ports and ones in the back which are connected directly to the motherboard. The front case ports are wired and may not be shielded very well but the back ports do not have that issue. There is also a power difference between what the front and back ports are capable of. Sometimes if I plug a usb 2.0 flash drive into my front ports (easier access) I get a warning from the system that they are not capable of high speed and I would be better off using a different port. Have you tried a back port?