A Kernel comparison via the Phoronix Test Suite.
Processor: Intel Core i7-4558U @ 3.30GHz (4 Cores), Motherboard: ASUS UX301LAA v1.0, Chipset: Intel Haswell-ULT DRAM, Memory: 8192MB, Disk: 2 x 128GB SanDisk SD6SP1M1, Graphics: Intel Device 0a2e (1200MHz), Audio: Intel Haswell-ULT HD Audio, Network: Intel Wireless 7260
OS: Ubuntu 14.04, Kernel: 3.15.0-031500-generic (x86_64), Desktop: Unity 7.2.2, Display Server: X Server 1.15.1, Display Driver: intel 2.99.914, OpenGL: 3.3 Mesa 10.3.0-devel (git-e9a4e74 2014-08-18 trusty-oibaf-ppa+gallium-nine), Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 2560x1440
Compiler Notes: --build=x86_64-linux-gnu --disable-browser-plugin --disable-libmudflap --disable-werror --enable-checking=release --enable-clocale=gnu --enable-gnu-unique-object --enable-gtk-cairo --enable-java-awt=gtk --enable-java-home --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-multiarch --enable-nls --enable-objc-gc --enable-plugin --enable-shared --enable-threads=posix --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-abi=m64 --with-arch-32=i686 --with-arch-directory=amd64 --with-multilib-list=m32,m64,mx32 --with-tune=generic -v
Processor Notes: Scaling Governor: intel_pstate performance
Graphics Notes: SNA
System Notes: This was running on battery power.
OS: Ubuntu 14.04, Kernel: 3.16.1-031601-generic (x86_64), Desktop: Unity 7.2.2, Display Server: X Server 1.15.1, Display Driver: intel 2.99.914, OpenGL: 3.3 Mesa 10.3.0-devel (git-e9a4e74 2014-08-18 trusty-oibaf-ppa+gallium-nine), Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 2560x1440
Kernel Notes: i915.enable_fbc=1
Compiler Notes: --build=x86_64-linux-gnu --disable-browser-plugin --disable-libmudflap --disable-werror --enable-checking=release --enable-clocale=gnu --enable-gnu-unique-object --enable-gtk-cairo --enable-java-awt=gtk --enable-java-home --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-multiarch --enable-nls --enable-objc-gc --enable-plugin --enable-shared --enable-threads=posix --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-abi=m64 --with-arch-32=i686 --with-arch-directory=amd64 --with-multilib-list=m32,m64,mx32 --with-tune=generic -v
Processor Notes: Scaling Governor: intel_pstate performance
Graphics Notes: SNA
System Notes: This was running on battery power.
Processor: Intel Core i7-4558U @ 3.30GHz (4 Cores), Motherboard: ASUS UX301LAA v1.0, Chipset: Intel Haswell-ULT DRAM, Memory: 8192MB, Disk: 2 x 128GB SanDisk SD6SP1M1, Graphics: Intel Device 0a2e (1200MHz), Audio: Intel Haswell-ULT HD Audio, Network: Intel Wireless 7260
OS: Ubuntu 14.04, Kernel: 3.15.0-031500-generic (x86_64), Desktop: Unity 7.2.2, Display Server: X Server 1.15.1, Display Driver: intel 2.99.914, OpenGL: 3.3 Mesa 10.3.0-devel (git-e9a4e74 2014-08-18 trusty-oibaf-ppa+gallium-nine), Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 2560x1440
Compiler Notes: --build=x86_64-linux-gnu --disable-browser-plugin --disable-libmudflap --disable-werror --enable-checking=release --enable-clocale=gnu --enable-gnu-unique-object --enable-gtk-cairo --enable-java-awt=gtk --enable-java-home --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-multiarch --enable-nls --enable-objc-gc --enable-plugin --enable-shared --enable-threads=posix --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-abi=m64 --with-arch-32=i686 --with-arch-directory=amd64 --with-multilib-list=m32,m64,mx32 --with-tune=generic -v
Processor Notes: Scaling Governor: intel_pstate performance
Graphics Notes: SNA
System Notes: This was running on battery power.
Testing initiated at 28 August 2014 18:19 by user michael.
Compiler Notes: --build=x86_64-linux-gnu --disable-browser-plugin --disable-libmudflap --disable-werror --enable-checking=release --enable-clocale=gnu --enable-gnu-unique-object --enable-gtk-cairo --enable-java-awt=gtk --enable-java-home --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-multiarch --enable-nls --enable-objc-gc --enable-plugin --enable-shared --enable-threads=posix --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-abi=m64 --with-arch-32=i686 --with-arch-directory=amd64 --with-multilib-list=m32,m64,mx32 --with-tune=generic -v
Processor Notes: Scaling Governor: intel_pstate performance
Graphics Notes: SNA
System Notes: This was running on battery power.
Testing initiated at 28 August 2014 18:29 by user michael.
Processor: Intel Core i7-4558U @ 3.30GHz (4 Cores), Motherboard: ASUS UX301LAA v1.0, Chipset: Intel Haswell-ULT DRAM, Memory: 8192MB, Disk: 2 x 128GB SanDisk SD6SP1M1, Graphics: Intel Device 0a2e (1200MHz), Audio: Intel Haswell-ULT HD Audio, Network: Intel Wireless 7260
OS: Ubuntu 14.04, Kernel: 3.16.1-031601-generic (x86_64), Desktop: Unity 7.2.2, Display Server: X Server 1.15.1, Display Driver: intel 2.99.914, OpenGL: 3.3 Mesa 10.3.0-devel (git-e9a4e74 2014-08-18 trusty-oibaf-ppa+gallium-nine), Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 2560x1440
Kernel Notes: i915.enable_fbc=1
Compiler Notes: --build=x86_64-linux-gnu --disable-browser-plugin --disable-libmudflap --disable-werror --enable-checking=release --enable-clocale=gnu --enable-gnu-unique-object --enable-gtk-cairo --enable-java-awt=gtk --enable-java-home --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-multiarch --enable-nls --enable-objc-gc --enable-plugin --enable-shared --enable-threads=posix --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-abi=m64 --with-arch-32=i686 --with-arch-directory=amd64 --with-multilib-list=m32,m64,mx32 --with-tune=generic -v
Processor Notes: Scaling Governor: intel_pstate performance
Graphics Notes: SNA
System Notes: This was running on battery power.
Testing initiated at 28 August 2014 18:41 by user michael.