need advice for better solution, multithreadin or else?

Question

I have a device that is sending data after 90 mili seconds(windows based solution) , on the basis of data, after some operations, I have to send data to 20 other clients on tcp Simultaneously. What can be the better solution. Can timer based solution work? Need help. I have tried multithreading, but causing 100 percent CPU usage, thread.sleep() Function is also creating problem, bcoz sometimes tcp clients also takes time to respond.