Can't really help with NVidia drivers (other than to run the lastest, stable release version (non-beta). I currently run AMD Radeon cards on my media servers (well, one is Intel-IGP). "Display Driver Stopped Responding and Has Recovered" Error points to a video card or driver problem.

Be sure you are running the latest x51-R3 BIOS.

I'm guessing this is Windows-10/64?

What Amp/AVR are you using? All high-quality HDMI cables with AVR "in the middle", right?

What version of VNC ?

If you can, Turn off Skype for now (one less thing to worry about). Check for strange or un-needed background processes. ProcessExplorer and AutoRuns are good.

Update and/or Uninstall Dell Support Assist.

Update Intel-RST. If not installed, I suggest you DO NOT even install it.

What is your drive config like? Any SATA-SSD or m2-SSD?

Run CPUID HW-Monitor and watch temps.

I'm sure you would be happier if your media files played properly. Try installing Kodi v16.0 and see if they work from it. Just so you know, Kodi contains all required codecs internally. It's completely self-contained.

Thanks Tesla. To work through the points

Be sure you are running the latest x51-R3 BIOS. Confirmed. I am running version 1.2.4  - the latest.

I'm guessing this is Windows-10/64? Correct.

What Amp/AVR are you using? All high-quality HDMI cables with AVR "in the middle", right? The Samsung TV (JS8000) use came with a hub (OneConnect) for connecting AV components. http://www.samsung.com/hk_en/support/skp/faq/1070028 . The PC is wired via high quality HDMI to this. There is audio passthrough back out to a Sony BDVE290 although I rarely use this as the TV sound is good in comparision. I bought the BDVE290 years ago and it is due for replacement.

What version of VNC ? RealVNC® Server 5.3.0 (r15303) x64 (Dec 7 2015 09:59:23)

If you can, Turn off Skype for now (one less thing to worry about). Check for strange or un-needed background processes. ProcessExplorer and AutoRuns are good. Not really an option. I live in Asia whilst my parents are in the UK, it’s their main way of seeing their two year old grandson! Compatibility mode seems to have solved this problem. Any clue why? I wondered if this indicated that an older version of DX or similar was causing wider issues.

Update and/or Uninstall Dell Support Assist. I was on the latest version so I have tried uninstalling.

Update Intel-RST. If not installed, I suggest you DO NOT even install it. Updated driver to latest version. Not sure about UI or even if this matters.

User interface version:  14.5.0.1081

Driver version:  14.8.0.1042

ISDI version:  14.5.0.1081

What is your drive config like? Any SATA-SSD or m2-SSD? 256GB PCIe SSD (Boot) + 2TB (64MB Cache) 7200RPM SATA 6Gb/s

Run CPUID HW-Monitor and watch temps. Nothing seems out of the ordinary here. See attachment.

I'm sure you would be happier if your media files played properly. Try installing Kodi v16.0 and see if they work from it. Just so you know, Kodi contains all required codecs internally. It's completely self-contained. Installed Kodi and tried. Exactly the same issues.

Thanks for helping!

Duplicate post deleted.

Fine to use RealVNC for remote maintenance, but I disconnect before trying to play 1080p-AC3 videos. I've seen it drag things down as it tried to mirror all that to remote.

Strange about Skype. At least you have a work-around. I understand your use-case but I keep my Windows/Kodi machines very lean (to prevent performance issues).

Google Dell Support Assist. I was hoping that would help.

Run Crystal Disk-Mark on both drives

Strange Kodi v16 didn't help. I'm running all sorts of files with no problems. Including ...

MKV made with MakeMKV - Full quality file from recent BD - 1080p and HD-Video

Even files straight from newer BD (.m2ts) ... not even converted to MKV.

One system is just an Intel-i3 with Intel-2000 IGP, but that's to my old 720p plasma. Strangely, I had to turn off DXVA2 on this system ... works much better. Also found this:

http://forums.***.net.au/archive/2432897

My main living-room Kodi Media-Center PC is pretty old also:

Intel Core2 Duo e6600 2.4Ghz, AMD-ATI XFX 5670 1gb PCIe
Onkyo 607 AVR, Epson 8350 1080p projector, Polk-Audio full-sized 7.1 set with Sub

However, both are still on Win7/64 (but I don't think Win10 is the root of your problems).

Keep trying to simplify (software and hardware) and update until you have something stable and working 100%. Then, you can slowly work your way back to required config.

I keep forgetting the x51 is a laptop/desktop hybrid.

You aren't having an Intel/nVidia Optimus issue are you?

Thanks for your help again.

• I tried disabling the VNC server. This triggered two 'Display Driver Stopped Responding and Has Recovered' errors and hasn't improved video playback.
• See below for Cristal Mark results on the two drives. Some of the HDD drive results look very low in comparison to the SSD scores,but I'm not sure of the benchmark on this. 
• I can play 4K video flawlessly. Two of the files above that play fine are 4K and have bitrates of 60MB/s. This led me to think it was a codec issue, but I can't see any pattern in the codec of the files that have the stutter issue. It does however do it consistently on files that play flawlessly on the TV's internal processor using USB.
• Not sure about Nvidia Optimus. What would I do to disable this and test? Couldn't find anything clear online.  

-----------------------------------------------------------------------
CrystalDiskMark 5.1.2 x64 (C) 2007-2016 hiyohiyo
Crystal Dew World : http://crystalmark.info/
-----------------------------------------------------------------------
* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]
* KB = 1000 bytes, KiB = 1024 bytes

Sequential Read (Q= 32,T= 1) : 1552.520 MB/s
Sequential Write (Q= 32,T= 1) : 306.834 MB/s
Random Read 4KiB (Q= 32,T= 1) : 707.789 MB/s [172800.0 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 304.258 MB/s [ 74281.7 IOPS]
Sequential Read (T= 1) : 1119.960 MB/s
Sequential Write (T= 1) : 307.887 MB/s
Random Read 4KiB (Q= 1,T= 1) : 40.919 MB/s [ 9990.0 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 174.556 MB/s [ 42616.2 IOPS]

Test : 1024 MiB [C: 35.0% (79.9/228.4 GiB)] (x5) [Interval=5 sec]
Date : 2016/04/01 8:20:33
OS : Windows 10 Professional [10.0 Build 10586] (x64)

-----------------------------------------------------------------------
CrystalDiskMark 5.1.2 x64 (C) 2007-2016 hiyohiyo
Crystal Dew World : http://crystalmark.info/
-----------------------------------------------------------------------
* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]
* KB = 1000 bytes, KiB = 1024 bytes

Sequential Read (Q= 32,T= 1) : 215.932 MB/s
Sequential Write (Q= 32,T= 1) : 209.773 MB/s
Random Read 4KiB (Q= 32,T= 1) : 1.548 MB/s [ 377.9 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 1.393 MB/s [ 340.1 IOPS]
Sequential Read (T= 1) : 214.960 MB/s
Sequential Write (T= 1) : 213.261 MB/s
Random Read 4KiB (Q= 1,T= 1) : 0.638 MB/s [ 155.8 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 1.398 MB/s [ 341.3 IOPS]

Test : 1024 MiB [D: 0.0% (0.2/1862.9 GiB)] (x5) [Interval=5 sec]
Date : 2016/04/01 8:26:40
OS : Windows 10 Professional [10.0 Build 10586] (x64)

1. I tried disabling the VNC server. This triggered two 'Display Driver Stopped Responding and Has Recovered' errors and hasn't improved video playback.   2. See below for Cristal Mark results on the two drives. Some of the HDD drive results look very low in comparison to the SSD scores,but I'm not sure of the benchmark on this.    3. I can play 4K video flawlessly. Two of the files above that play fine are 4K and have bitrates of 60MB/s. This led me to think it was a codec issue, but I can't see any pattern in the codec of the files that have the stutter issue. It does however do it consistently on files that play flawlessly on the TV's internal processor using USB.   4. Not sure about Nvidia Optimus. What would I do to disable this and test? Couldn't find anything clear online.

1. You don't have to disable it. Just don't be using it (connected to it remotely). Just leave it "waiting for connect".

2. See above post

3. Oh, ok ... Some 4K (mkv ?) files play 100% perfectly. Did you make the other files that play poorly? Could be anything from codecs to encoding process. Kodi should take care of any codec problems (why I suggested it in the first place).

4. Good chance that this is your problem. I suggest you try to make sure that NVidia-960 is being used (hopefully exclusively, if that's possible).

http://www.dell.com/support/article/us/en/19/SLN146534

5. Be sure Windows Power Profile is set to High Performance.

Sequential Read (Q= 32,T= 1) : 215.932 MB/s
Sequential Write (Q= 32,T= 1) : 209.773 MB/s

- Looks good for a spinning HDD

Sequential Read (Q= 32,T= 1) : 1552.520 MB/s
Sequential Write (Q= 32,T= 1) : 306.834 MB/s

- SSD Read is ok, but what's up with Write. Even IOPS are low.

SDD and Cristal Mark

Checking against the manfactor specs for this drive it seems like the results are broadly in line with their reported performance.

http://www.samsung.com/semiconductor/products/flash-storage/client-ssd/MZVLV256HCHP?ia=831

Video

No I didn’t make the video files.  I get the same behaviour in Kodi as MPC-HPC. The same files stutter and the same files play flawlessly. The files that stutter though play perfectly on the tv’s internal processer. This makes me think it something to do with the layer below the codec ie the decoder (DXVA2) and drivers rather than the codec. Given the plane9 visualiser also crashed and had I skype/onedrive difficulties this would makes senses that it was not a codec issues per se, but something where the codec is interacting with the lower lay feature. Either,

• Video drivers or direct X is some way corrupt
• There is a bug in one of these layers
• The hardware has some fault not spotted through the tests
• There is some incompatible hardware or software that isn’t playing happily with the GTX960

I wonder if someone from Dell could advise if other customers have reported something similar?

NVIDIA Optimus

I don’t think this is relevant for me. The X51 R3 is not shown as one of the supported systems and when I try and follow the instructions, ‘Preferred graphics processor’ is not shown on either the global or program settings tab.