According to Matrox's web site and documentation the VS4 only works with Microsoft Windows 7 (64 bit) with Service Pack 1

We ordered VS4 anyway. When it arrives we will test if it works with 8.1. I try to remember to update here.

I have been speaking with Matrox engineers now for several weeks and according to them the vs4 card is not supported in 8.1 however they have a set of beta drivers which are in testing and they are hoping to release them some time this summer. They are aware of vmix and Martins recommendation of moving to 8.1. My only concern with Matrox is how long it is taking them to update the drivers. Their card is about a $500 premium over the decklink quad card and I have to imagine there are a bunch of us expecting quicker driver updates

Now I have done some more testing. Four cameras work ok with matrox vs4, win 8.1 pro, vmix 4K. System is much more stable than four independent BMD decklink minirecorder pcie cards. Our pc can do the following at the same time with vs4 (format 1280x720 50p):

- four camera iso recording
- five video delays (20s, 4 cameras and output mix)
- mp4 recording of output mix
- one overlay (tested with text ticker), probably can do more layers too - have not tested
- basic mixing of cameras
- running video delays
- running video inserts (prores LT)
- external out (sdi deckling mini monitor)
- one monitor attached (vmix program window)
- audio in with usb audio mixer

Above mentioned setup works fairly well in test bench. When saving five video delays the processor load is 60-70 percent (this means that pc records 10 hd streams at the same time). I should test it also in real situation and run many many hours to make final conclusions .

If I attach one more monitor for full screen out (multivew or master out) set up is stable few minutes but then it suddenly starts to get 20-80 ms render times and multivew starts to slow down and delay in external sdi out can be few seconds. This is weird because gpu load is very low. But without second monitor setup seem to work well.

Wish list: dvcprohd codec and support for two vs4. Multiview in second display would also be nice, but some why it seem not to work well.

We are running win 8.1 and driver mtxutils_21.exe (downloaded in may 15.)

Vmix must be installed before installing mtxutlis driver (though should not do blue screen with out it). We did nothing special, put vs4 into its place and installed driver and that’s it. Vmix was already installed.

Motherboard issue?