Turning off hardware acceleration

[Jroper]

Why is it that turning off Hardware Acceleration sometimes helps speed up a system or prevent it from crashing?  This seems counterintuitive.  What exactly helps AutoCAD by turning it off?

[Anonymous]

how it interacts with the video card for memory, etc.  i find that I get better visual results sometimes with it off.  in part from using WIndow7, the system reports more memory on the card than there actually is because the operating system can donate system ram to the video (i think) so this is why having a certified card becomes more important (not that i've spent money for the more expensive "suggested" hardware....)

does this help?

[Alfred.NESWADBA · Accepted solution]

Hi,

compare it with two people working together on one project, but have different jobs to do.

In one case they speak the same language, but these two guys are doing their work quite slow. As they speak the same language the orders they give to each other are well understood and so clear for everyone.

The second case is now you have two guys that are specialists, they do their jobs great but they don't speak the same language. The result is that the orders they give are not clear to understand, there may be some misunderstandings or there may be that there are some questions to repeat the order with other words to make it understandable.

The first case is AutoCAD and the internal software-driver, hw accerator off (both are speaking "Autodesk-language") and as they have no GPU they are slow, yes. 😉

The second case is AutoCAD and a gc-driver, hw acceleration on. Now the language they comunicate is "DirectX", but AutoCAD doesn't use now the primary language "Autodesk-language", but DirectX with dialect A ..... and the gc-vendor uses not the primary (e.g.) nVidia-language, the vendor also has to use the foreign language DirectX with dialect B.

And as there are different version of DirectX + different interpretations of how these function do have to interface each other there may be more or less communication-problems. If you get a pairing of AutoCAD version, OS version and gc driver version that can communicate better you will have better success using the hw acceleration, otherwise turning it off has advantages.

Hope the story is not too long and the comparision between people and language to gc + drivers/interfaces is good to understand.

- alfred -

[Jroper]

I think it is starting to makes sense.  I helped a guy that had a huge 2D file with a ton of entities by turning off the hardware acceleration.  I guess the software driver is better at loading and displaying a bunch of flat entites.  The 3D card (a Quardo 2000 FX) isn't so good at this because it is trying to "speak a different language" or it is taking resources that are not helping.  But if he were trying to draw and render a 3D pipe valve, then the 3D card would have the advantage.  Am I understanding correctly?

[Alfred.NESWADBA]

Hi,

>> But if he were trying to draw and render a 3D pipe valve, then the 3D card would have the advantage. 

>> Am I understanding correctly?

Yes, mostly. 😉

There are more advantages using some visual style that uses some kind of rendering/shading compared to visual styles like 2D-wireframe.I don't think that it is so important if you have 2D or 3D geometry, it's the visual style that uses more or less acceleration on the GPU.

Of course shaders/render-engines are more optimized on working with faces than working with wireframe.

- alfred -