Results: Metro: Last Light
Like many of the games we're using to test these entry-level graphics cards, Metro: Last Light is not a casual title. It can be brutally demanding, in fact. To make it run well on these modest GPUs, we're forced to drop the detail levels as low as they'll go at 1280x720.
Even at 720p, this game is an insurmountable challenge for some of these cards. It takes a Radeon HD 6670 equipped with GDDR5 memory to maintain a minimum frame rate around the 30 FPS level.
Lower-end offerings like the GeForce GT 640 and Radeon R7 240 really only dip below 30 FPS briefly during one demanding part of the test, so I'll begrudgingly call them playable as well. But the Radeon HD 6670 DDR3 and GeForce GT 630 GDDR5 do not give us acceptable performance.
Fortunately, the frame time variance averages are pretty low. There are a few spikes during the benchmark, but nothing we'd flag as an issue for one card or another.
At 1920x1080, many cards are forced under 30 FPS for extended periods of time. The Radeon R7 250 is still probably playable, since they only fall under the threshold briefly. But for a smoother experience, you'd want at least a Radeon HD 7750 or 7770.
A majority of cards demonstrate low variance with occasional spikes, but the Radeon R7 240, GeForce GT 630 GDDR5, GeForce GT 640, and Radeon HD 6670 DDR3 really struggle at this resolution.