Update: Samsung has posted an official response to yesterday's benchmark kerfuffle, explaining that the maximum frequency for the S4 is actually 533MHz, but that it is actually scaled down for "certain gaming apps that may cause an overload". The maximum frequency, according to the statement, is also attainable in "apps that are usually used in full-screen mode" like the gallery, S Browser, etc. This may not fully explain the explicit mention of certain benchmark apps in TwDVFSApp, but it is at least nice to see an official response to the situation.
Here's the full statement:
Under ordinary conditions, the GALAXY S4 has been designed to allow a maximum GPU frequency of 533MHz. However, the maximum GPU frequency is lowered to 480MHz for certain gaming apps that may cause an overload, when they are used for a prolonged period of time in full-screen mode. Meanwhile, a maximum GPU frequency of 533MHz is applicable for running apps that are usually used in full-screen mode, such as the S Browser, Gallery, Camera, Video Player, and certain benchmarking apps, which also demand substantial performance.
The maximum GPU frequencies for the GALAXY S4 have been varied to provide optimal user experience for our customers, and were not intended to improve certain benchmark results.
Original Post: According to a report from Anandtech earlier today, Samsung might be selectively causing hardware in the Galaxy S4 to over-perform in certain benchmark apps, skewing results in its favor while frequencies achieved during the tests aren't available elsewhere.
Essentially, Anandtech explains, the Galaxy S4's GPU normally clocks in at 480MHz. The official figure isn't explicitly advertised by Samsung, but a variety of tests seemed to prove the frequency as normal, at least until it came to benchmarks.
Anandtech reports that upon launching certain apps, GPU frequency jumps to 532MHz (an ~11% boost), and the device's CPU governor is fixed regardless of what the app is actually doing. The GPU findings are specifically related to the Exynos variant, while CPU performance is affected in both Exynos and Qualcomm-powered versions of the S4.
It turns out, according to the post, that an app (TwDVFSApp.apk) is responsible for changing DVFS (Dynamic Voltage and Frequency Scaling) settings such that certain apps (whose package names are actually coded into TwDVFSApp) can "boost" performance. The apps include benchmark standards like AnTuTu, Quadrant, GLBenchmark 2.5.1, and others.
As the Verge rightly notes in its coverage, benchmarks have never been a completely accurate mirror for real-world user experience, but as Anandtech explains, Samsung's optimizations could set an unsavory precedent, encouraging SoC and device makers to focus on "gaming the benchmarks rather than improving user experience."
At the time of writing, Samsung has declined to comment on the matter. We'll let you know if that changes.
For a fully detailed explanation, hit the source link below.