Radeon HD 7690M/6770M Overclocking Experiment
The AMD Radeon HD 7690M XT found in lots of HP laptops at the moment is already an overclocked card–the HD7690M is actually an HD 6770M with a higher memory clock–so it should have been unlikely to go much further, but as it turns out it’s actually possible to squeeze a few extra frames per second out of this GPU. These results should also apply to the HD 6770M, as there are no apparent changes between that chip and the 7690M besides the increased memory clock.
As usual, this is just an experiment and not an instruction manual. Overclock at your own risk. Besides, individual chips are not created equal, so your mileage may vary. Some would also argue that it’s unnecessary and/or risky to overclock your laptop GPU, and they may have a point, but as long as you keep track of your temperature readings there is no real difference from overclocking a desktop GPU (which may also shorten the chip’s life span and cause system failure eventually).
At any rate, the specimen we will be torturing today is a 7690M XT (models without the ‘XT’ should have the same potential) found in an HP Envy 17 (3D). This is an upper-midrange 40nm GPU that will run most games at the display’s native 1080p resolution, but it has trouble keeping up with the stereoscopic 3D feature turned on without lowering the resolution and detail settings. Some demanding games like Battlefield 3 are also just barely playable in Full HD, but more on that particular game later.
The base clocks are 725 MHz for the core and shaders and 900 MHz for the GDDR5 video RAM, the latter of which is the main difference in the HD 6770M, which has an 800 MHz memory clock. To increase the clocks in this graphics card, the Sapphire Trixx overclocking tool is your best bet, and Furmark to run stability tests and verify temperatures and clock rates.
Temperature is not much of a problem in this case, as it keeps hovering above 70 degrees C regardless of the clock rate (with the help of an Envy 17 cooling fan running at full capacity). What likely limits the card is instead the voltage setting, but modifying that one is something that you generally want to avoid, because this is where things tend to get really nasty.
While running Furmark, the 7690M core speed managed to reach 835 MHz before the driver started to crash–a 15% improvement. Somewhat surprisingly, the memory clock went from 900 MHz to 1070 MHz without causing problems–an improvement of about 19%. The results with these clocks in the Futuremark benchmark suite were as expected, with the greatest improvement seen in 3DMark 11, followed by Vantage and 3DMark 06, which is more CPU dependent.
Now to return to Battlefield 3, which is barely playable in the Low preset at 1920×1080 with the Envy 17. Does the frame rate improve? Why yes, but only by about 13%. This is not much, but it does help the game stay above 30 FPS for the most part. On the other hand, the test scene is the first single player mission. Multiplayer battles may be tougher on the GPU.