The GPU core power shown + 40-50 W for the PCI-E slot power on the riser (not shown) is your total power. Your miner gets new work from the pool and you send the completed work back as shares. The lower difficulty the shares, the more frequently your miner completes the work and sends the shares back to the pool. A higher difficulty share takes longer to complete, but is worth more than a lower difficulty share e.g. At diff 4000 shares are worth twice as much as diff 2000 shares.