I think that’s indicative of a resource issue…V5 uses probably around 1% of your GPU’s resources… V6 will use 100% of your GPU’s resources if it needs to. Just to give an example…
Your laptop is running at 3840 x 2160… which means just the screen alone requires a minimum of 32MB of video memory just to store what you’re seeing on your desktop. Each viewport in Rhino V6 is managed by a Multi-sampled frame buffer and a single frame buffer… A frame buffer consists of a 32bit RGBA buffer and a 32bit floating point Depth and Stencil buffer…and take note what I said above…there are two frame buffers per viewport (a sampled one (AA) and a non-sampled one).
Given that, let’s make things simple to work with… Suppose when Rhino starts up it uses the screen real estate uniformly … So a 4 view layout means that you would have 4 views each running at 1920x1080… So lets break down the memory usage…
1 Viewport would be:
1 Sampled Color Buffer at 1980 x 1080 x 4 x AA … so for 8x AA that’s 1980x1080x32 = ~65MB
1 Sampled floating point Depth/Stencil buffer at 1980x1080 x 4 x AA … again, at 8x that’s ~65MB
1 Non-sampled Color buffer at 1980 x 1080 x 4 = ~8MB
1 Non-sampled floating point Depth/Stencil buffer at 1980x1080x4 = ~8MB
…for a grand total of 65 + 65 + 8 + 8 = ~145MB …just in buffers alone
Since there are 4 viewports, that’s 4 x 145, which is roughly 580MB of video memory that must be managed contiguous memory by the drivers… That’s over 25% of your current VRam that you currently have…and that’s just talking about the frame buffers… There’s also the screen buffer I mentioned, which is another 32MB, and now thrown in your second monitor, which now also requires a block of contiguous memory just to manage what you see on it …
Rhino V6 then also starts allocating GPU memory for almost every thing you see in your model… So things can start adding up quickly… Now, I realize that so far I’ve only accounted for about 35% of your VRam…but you asked why V5 doesn’t show this problem…and I’m guessing because V5 doesn’t instantly use up 25% of your video memory just to start up and create a 4View layout.
Whether this is actually the reason is purely speculation on my part…
P.S. How the drivers choose to manage the memory once it becomes largely blocked like this is also a factor, and an unknown on my part.