To enhance the performance of devices running on Android, the Android Open Source Project (AOSP) team release the M-series of CyanogenMod 10.1 for some devices, including the U.S. models of Samsung Galaxy S3 and all variants of Google Galaxy Nexus.

So far, all the devices were running on nightly mode of CM 10.1. The M-series build are more stable than the nightly build.

"Today we are doing our first M build for 10.1, based on Jelly Bean MR1. More devices are being worked on, and are available as nightly builds for the time being," CyanogenMod posted on its official Web page.

The date when the M-series CM 10.1 will be available for other deices was not disclosed.

The devices for which the M-series is now available are:

Samsung Captivate
Samsung Nexus S (+4G)
Samsung Galaxy S3 USA models (D2*)
Samsung Galaxy S (galaxysmtd/galaxysbmtd)
Google Nexus 7
Google Galaxy Nexus (all variants)
Google Nexus 4
Google Nexus 10
ODroid
Samsung P3100, P3110
Samsung P5100, P5110

M-builds cannot be considered perfect as they are also available under the tag, 'EXPERIMENTAL' and always have versions. The recent M-series build available for CM 10.1 is under M1 series.

Late last year, CyanogenMod posted on its Web page that in order to bring more stability to the users-experience it will start releasing the M-series build in the beginning of every month. It then stopped the release of M-series build after releasing M2 for so many devices.

The reason behind stopping the update was to get more time to concentrate on building CyanogenMod 10.1.

"With CM10 we started doing "M-Series" builds every month. These builds are intended to be mostly stable and ready for everyday use. We suspended building these after the initial release in order to focus on 10.1, which is now on track to a stable release," the post on the official Web page reads.

If you own any of the devices mention above, you can straight away head to Get.cm to download the M1-series CM10.1 for your device.