Metro 2033 is an older title, but it still presents modern hardware with a taxing workload. It's notorious for being GPU-limited, so we're not expecting CPU performance to make a massive difference in this game's outcome (at least, based on the data we've generated up until now).
Most of our CPUs maintain an average of at least 50 FPS. The dual-core A4s and the Athlon II X3 fall under 40, and the Pentium G860 sits in between with a 47 FPS average.
The minimums are similar across the board, suggesting that something other than the varying CPUs is dictating the performance floor.
Compare these results to what we saw in Picking A Sub-$200 Gaming CPU: FX, An APU, Or A Pentium? a year ago. You'll notice that the average frame rates are up on almost all of the CPUs except for Intel's Pentium G860 and AMD's Athlon II X3. At the time, the Radeon HD 7970 we used was brand new, and its drivers were decidedly immature, which may help explain why a similar-performing GeForce GTX 680 fares better today.
It's quite clear that the processors we're testing limit most of the first half of this benchmark, while the GPU load picks up about two-thirds of the way in, pulling all test beds down under 20 FPS.
In general, the results are very good news for folks with inexpensive processors, since we're seeing low latencies between consecutive frames. The dual-core A4s are the worst performers by far, with a 95th percentile lag time of about 20 milliseconds.
How about a bit of perspective? On average, the A4 APUs run at about 35 FPS. That 20-millisecond lag would insert a single frame corresponding to around 20 FPS. If that happened once every 100 frames, at 35 FPS, it would happen about once every 2.5 seconds. That's an oversimplification because the percentile is pulled from the entire course of the benchmark, but it's a useful way of imagining what's going on.
On the other hand, the Pentium G860 and Athlon II X3 450 experience a roughly 10-millisecond lag at the 95th percentile, representing a single frame time drop at 40 FPS down to an equivalent 30 FPS. That's not as big of a difference. Only the FX-4300, A10-5800K, and FX-4170 have a 95th percentile lag of more than eight milliseconds. The rest of the field is under six, and we consider that result statistically insignificant.