Before you pin the blame on the sound card, please make sure the system that is connected to the wall outlet has a proper grounding/earthing made all the way to your MDB(main distribution board) and if the static is persistent on other audio devices. If so you may need to change the placement of your system(as in, change to another wall outlet in your room/house or use
ferrite chokes between the sound card output to your speaker input or source an analog audio cable that has a ferrite choke on each end. It may be a good to get your grounding checked by an electrician since it can and will hamper other components in your system.
It'd help us two fold if we could learn of your full system's specs inclusive of your OS. Was this issue always present? When did the issue crop up?