GPU Mining is a bitcoin mining based website. It uses the latest mining hardware like GPUs, CPU's & FGPA to ensure the highest bitcoin mining speed. It is one of the highest paying free bitcoin mining company. It also provides affiliate referral program. From which every free user can get a 20% referral bonus. If you want to earn more than upgrade to premium plans and get real benefit of bitcoin mining. In premium plans, you can get up to a 100% referral bonus.