How to set Plot settings GPU

  • Hello guys. I want to plot my drives with my GPU because with my notebook i get on CPU only 2500 nonces/min. I can run my CPU only on 1.98GHz. If i increase it the Notebook overheats. That's Why i want to use GPU. Do you have any idea how to set the device.txt and stagger size?
    My system:
    i5-2410M 2.3 GHz
    8GB RAM (5GB usable)
    AMD Radeon HD 6850M 1GB

    I thought it would be better to plot with this GPU so it would go faster than 24 hours or above for 1TB. Hope anyone could help me.