Hi puzzle3, welcome to TSF
Do you have any other programs running in the background while gaming? Also, check to see if you have any programs scheduled to start running after a set period of no activity or at a certain time after starting Windows.
Check your temperatures and voltages with PC Wizard at startup with no other programs running. Take with a screenshot from the 'Voltage, Temperature & Fans' window. Leave it open on the desktop and take another screenshot of PC Wizard during gameplay when it starts to lag by pressing alt-tab to switch back to the desktop. Post back with both screenshots so we can see how your system copes under stress. If PC Wizard doesn't show the graphics card temperature, use the nvidia control panel to see it.
Open the case and post back with the details from the PSU label (make/model, total watts, amps for +12V)
Do you have any other programs running in the background while gaming? Also, check to see if you have any programs scheduled to start running after a set period of no activity or at a certain time after starting Windows.
Check your temperatures and voltages with PC Wizard at startup with no other programs running. Take with a screenshot from the 'Voltage, Temperature & Fans' window. Leave it open on the desktop and take another screenshot of PC Wizard during gameplay when it starts to lag by pressing alt-tab to switch back to the desktop. Post back with both screenshots so we can see how your system copes under stress. If PC Wizard doesn't show the graphics card temperature, use the nvidia control panel to see it.
Open the case and post back with the details from the PSU label (make/model, total watts, amps for +12V)