You need to edit the thresholds for G-states of your card.
The section of macmodel i'm using (for me it's iMac12,2)
GTX570 - DeviceID1086.
Code:
<key>iMac12,2</key>
<dict>
<key>Vendor10deDevice1086</key>
<dict>
<key>Heuristic</key>
<dict>
<key>ID</key>
<integer>0</integer>
<key>IdleInterval</key>
<integer>150</integer>
<key>SensorOption</key>
<integer>1</integer>
<key>SensorSampleRate</key>
<integer>4</integer>
<key>TargetCount</key>
<integer>5</integer>
<key>Threshold_High</key>
<array>
<integer>55</integer>
<integer>75</integer>
<integer>100</integer>
</array>
<key>Threshold_Low</key>
<array>
<integer>0</integer>
<integer>87</integer>
<integer>95</integer>
</array>
</dict>
<key>LogControl</key>
<integer>1</integer>
<key>control-id</key>
<integer>18</integer>
</dict>
<key>default-control-id</key>
<integer>18</integer>
</dict>
For GTX570 there are 3 PM states ("Threshold_High/Low" sections). For any other card the number of states may differ.
I dont know how to find out the number of states at the particular card.