I have a dual monitor setup with 2 24" monitors @ 1920x1080

AMD FX-8320
MSI GeForce N610-2GD3H
8G RAM

source: 1080p@50fps (mts), for details see below

When I play an uncut movie, only the clips have been added, the video and the audio _could_ be acceptable on the _1st_ monitor, but it could stutter too. If I double click on the monitor, I see an image on the 2nd monitor, but after a few seconds video and audio start to stutter. cpu is very low, when I check with top.

Format : BDAV
Format/Info : Blu-ray Video
File size : 85.9 MiB
Duration : 28s 794ms
Overall bit rate mode : Variable
Overall bit rate : 25.0 Mbps
Maximum Overall bit rate : 28.0 Mbps

Video
ID : 4113 (0x1011)
Menu ID : 1 (0x1)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Format settings, GOP : M=3, N=24
Codec ID : 27
Duration : 28s 280ms
Bit rate mode : Variable
Bit rate : 23.6 Mbps
Maximum bit rate : 25.0 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 50.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.228
Stream size : 79.7 MiB (93%)

Audio
ID : 4352 (0x1100)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : 129
Duration : 28s 320ms
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Compression mode : Lossy
Delay relative to video : -40ms
Stream size : 1.30 MiB (2%)

Text
ID : 4608 (0x1200)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 27s 776ms
Delay relative to video : -40ms

Now I know, that the hardware is strong enough, it can work without stutter on the 2nd monitor. Maybe it depends on which monitor the kedenlive-file was created before. I did a "save as" and then I got an acceptable result.