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DVFS gives 20% better battery life to the N95

4 replies · 2,889 views · Started 28 November 2007

slitchfield 28 Nov 2007, 13:19

Apologies for linking to an AAS comment thread already half-linked below, but an AAS user has been doing battery benchmarks for two N95's, one with old v12 firmware and one with the new v20 with DVFS (Dynamic Voltage and Frequency Scaling), it seems that for low-CPU tasks like music playback, the battery is used more efficiently, with the underclocking resulting in 20% longer battery life from the BL-5F.

Read on in the full article.

Unregistered 09 Dec 2007, 14:48

The underclocking has led to some quite jerky video playback with my N95 using Coreplayer. Perhaps due to Coreplayer's lower CPU usage, the N95 is detecting that less CPU power is needed, resulting in there not being enough horsepower to play videos smoothly.

Menneisyys 13 Dec 2007, 22:20

Unregistered wrote:The underclocking has led to some quite jerky video playback with my N95 using Coreplayer. Perhaps due to Coreplayer's lower CPU usage, the N95 is detecting that less CPU power is needed, resulting in there not being enough horsepower to play videos smoothly.

Interesting - do you have some before / after benchmark data so that we can see the difference? I've only made some serious benchmarks with v20 and, having no access to v12 N95's, can't remake these tests.

Unregistered 14 Dec 2007, 19:43

Basically, before upgrading, all my videos would play smooth as silk with realplayer/coreplayer (encoded with H.264/AVC at 25fps). With v20, even at lower frame rates, it stutters in both applications.
Using coreplayer's built in Properties dialog window, I can see that there are many dropped frames, compared with 0 with the previous firmware.
In Realplayer, the video just pauses for about 1 sec every 30 seconds or so, which didn't used to happen.

Benchmarks-wise, for H.264 video, I get between 90% and 105% compared with ~130% previously, and the sound stutters terribly during the v20 benchmark.
With normal Mpeg-4 (I'm assuming you know there's a difference between H.264 MP4 and Mpeg-4 MP4 - just different codecs really) the benchmark is around 150% compared with 130% previously.

Any ideas?