How much extra performance you can squeeze out of a laptop GPU differs a great deal between laptops–from none at all (locked BIOS) to an impressive amount of extra frames per second, suddenly making some games playable at higher detail settings and resolutions. Laptops specifically designed for gaming usually have better cooling and the Alienware M14x certainly belongs in this category. Even though it is relatively small for a gaming laptop, there’s nothing to complain about when it comes to cooling (although you might complain about the noise level).
As you would expect from a gaming PC manufacturer, Alienware makes pretty overclocker-friendly machines, but you perform the steps outlined here at your own risk. You get good frame rates in all games with the GT 555M anyway, so there’s no actual “need” for overclocking, but when the option exists it’s hard for any hardcore geek to resist.
Since overclocking by and large both depends on both the cooling capabilities of the laptop and is even known to vary between individual chips, there are no guarantees that you get the same results as us. Neither does this necessarily apply to any laptop with the NVIDIA GeForce GT 555M such as the Dell XPS 17 due to a different cooling layout. This might nevertheless give you some hint about what to expect from the GT 555M.
There are several apps available that will overclock your NVIDIA graphics card. Even NVIDIA itself has a tool, but we settled on eVGA Precision. It is of course intended for NVIDIA-based eVGA cards, but it is simple and straightforward and works just as well for other NVIDA cards. Precision has the convenient option to apply the new clocks at startup (not recommended when you are testing) and several monitoring tools including temperature. It also links the core and shader clocks. The fan speed in the Alienware M14x is set in the BIOS, so this option is grayed out.
The standard core clock for the GT 555M is 590MHz and for the memory 900MHz. To test how high it can go without producing artifacts or hanging, a good tool to use is Furmark (available for download here), which stresses the GPU to the max. There’s also a built-in “Test” tool in eVGA Precision, but this probably only works for eVGA cards (at least it didn’t work for us). At any rate Furmark is more than adequate if not better.
A conservative way of testing increased clock speeds is to up the sliders in Precision little by little, in 10MHz intervals for example, until you start to notice artifacts or worse, that the driver hangs. You run Furmark and watch the temperature increase until it stabilizes at a certain level and stays there. Let it run for a while to make sure that it stays stable before testing a higher clock speed.
The “sweet spot” for our M14x was 752MHz for the core clock (1504MHz for the shaders when linked) and the maximum 1080MHz for the memory clock. When the core clock started to reach 800MHz the driver would hang and restart. After countless hours of gaming in Dragon Age 2, Fallout 3, Civ 5 and other games via Steam as well as several shorter benchmarking runs it has remained completely stable. One of the Fallout 3 DLCs did hang (Operation Anchorage), but this turned out to be due to be a problem with the game itself.
Here are the results from the Futuremark 3DMark benchmarks with the new clocks, compared to the stock clocks that were used in our M14x review.
The overclocked system delivers as expected with the increased clock speeds. A 27 % improvement in 3DMark Vantage, 21 % in 3DMark 06 and 24 % in 3DMark 11 is more than OK and puts it roughly on par with the GTX 460 at stock speeds. How about the games then? Here are a few samples:
Again very nice improvements in frames per second ranging from 24 % in STALKER to 32 % in Dragon Age 2. These are not subtle changes but clearly noticeable ones; if a game is just barely manages to run at playable frame rates it will suddenly run completely stutter free. It may also be enough to make some games run at higher detail settings than they would otherwise.
Update: As Venceslas points out in the comments below it is to a certain extent the voltage that limits how high you can go with the GT 555M. This can be circumvented by using a custom BIOS (which no doubt voids the warranty). However, with this tip in mind it was too hard to resist the temptation, and it works. All of a sudden the GPU core clock could be taken beyond 800MHz and with the core set to 807MHz the M14x was stable and produced 14,247 points in 3DMark 06 instead of 13,574. Not a huge improvement and nothing worth voiding your warranty over but an interesting experiment nonetheless.