We’re really close to getting our hands-on CyanogenMod 12S for the OnePlus One. But until that day comes, all of the attention is squarely on OxygenOS, OnePlus’s homemade ROM based on Android 5.0.2. So far, the new software is holding up like a champ, performing well and generally handling everyday tasks with aplomb. While that’s all well and good, how does it actually compare to the older CyanogenMod 11S in terms of battery?

We ran a tests to find out.

Keep in mind that this is by no means a comprehensive battery review. We’re still going through some tests and figuring out how OxygenOS will hold up over the long run. What this test does, however, is provide a base, giving us an idea of how each respective software handles a specific task. Just because Oxygen keeps a charge longer when playing video doesn’t mean it won’t run out doing simple tasks like messaging and browsing the Web.

What we did is simple: We ran the same two tests on each phone, varying the control just slightly each time. For the first test, we turned the brightness on each phone all the way up, closed all applications (except for YouTube), and then ran a lengthy HD video with the volume on mute. Cellular data was turned off on the CyanogenMod; there was no cellular connection with our Oxygen model.

In the first test, we went for about 3 hours and 47 minutes, and after all was said and done, Oxygen had about 30-percent battery life, while Cyanogen 11S had about 5-percent. A pretty drastic difference. In the second test, we put both in airplane mode, turned the brightness all the way up, muted the volume, and closed all the applications except for YouTube. This test ran for about 4 hours and 18 minutes, and resulted in Oxygen having 25-percent battery, and Cyanogen having 14-percent.

We suspect that the main factor here is how optimized Lollipop is compared to Android 4.4.4, which CyanogenMod 11S is based off of. At least in terms of battery, OnePlus’s Oxygen appears to provide an upgraded experience; whether you think it provides an improved experience overall is up to you.

CyanogenMod 12S, which is based off Lollipop, has been certified, which means OnePlus One owners have that to look forward to in the future. That said, we’ll see how CM12S and Oxygen fare against each other once the update comes through. For now, check out the results we found in the video above.