It’s worth noting, there are some graphics cards that are simply not worth putting in the Amplifier. The Alienware 13’s GTX 860M is around the performance of a GTX 750 Ti (~$150 GPU), so anything around or lower than that will make no difference or even reduce performance. On the AMD side, this means anything around or lower than a Radeon R7 265. I would highly recommend spending at least $200 on a graphics card for the Amplifier to get a decent performance boost over what the GPU in the Alienware 13 already provides. So at least a GTX 760 or R9 280, though naturally higher is better.
With a reference GTX 780 in the Amplifier I was able to game on higher graphics settings easily. At 1080p, this card is suitable for playing pretty much any game on the market at near maximum settings with decent framerates, and provides around double the performance of the GTX 860M. For my time gaming on the Alienware 13 with the Amplifier, this meant cranking the settings up significantly while keeping the framerate relatively similar. Of course you could go the other way and get monster frame rates, but I preferred to play with graphical fidelity not previously achievable on this laptop. Games like Dragon Age Inquisition and Crysis 3, for example, could be played at mostly max settings with framerates above 40 FPS. Previously these games would have run at medium, so it’s a significant boost in graphical quality. To compare the performance of the Amplifier with a high-end GPU to the Alienware 13’s embedded GPU, I ran a selection of games with and without the Amplifier connected. I also compared the results with the Amplifier connected to our GTX 780 benchmarks on a high-end gaming system, which should indicate how the combination of a laptop and desktop GPU fare in terms of non-GPU bottlenecks. Also, keep in mind it’s possible to get even more performance by opting for the highest end card on the market, the GTX 980, rather than the GTX 780. The 780 actually is a discontinued product, but if you’re after roughly the same performance, an AMD Radeon R9 290 should do the trick, and can be found for under $300 these days.
Throughout the games I tested, the Graphics Amplifier benchmarked ~15% lower on average compared to our high-end desktop test bench with the same graphics card inside. Some of this will be down to a rough 5% reduction in performance due to the limited PCIe bandwidth, though I often noted that the GPU was running at nearly 100% utilization. Another explanation is that the CPU is being bottlenecked, which wouldn’t surprise me considering the Alienware 13 is powered by just a dual-core U-series CPU with a 15W TDP. In nearly all the games I tested, CPU utilization was approaching 100%, a situation that isn’t ideal for a gaming notebook. In more CPU heavy titles like Civilization: Beyond Earth (which I didn’t test), this bottleneck could seriously hurt performance. However the good news is that the Graphics Amplifier does significantly improve performance over the internal GPU. Performance essentially doubled across the games I tested, which when playing at maximum settings often meant going from unplayable to very acceptable frame rates. Chucking in an even more powerful GPU will result in even better scores. Thermally, the blower-style GTX 780 sat at around 80C during load in games, which is a typical result for this graphics card and good news for the thermal performance of the Amplifier with blower style cards. When I tried a Sapphire Radeon R9 290 Tri-X, which vents sideways and into the case, it sat at around 75 degrees during load, which is above the typical 70C it would sit at in a well ventilated PC case. The fan in the Amplifier runs all the time, so even when it’s idling you’ll get the noise of the fan in the background. During load, the Amplifier is still louder than the internal fans in the laptop (which run very quietly when the GPU isn’t being used), though its volume will depend largely on the cooling solution of your graphics card.