DX Memory Optimization

If there is not space left in the hardware, the driver will take something out and put what it needs in. This is ok in some cases where you wouldn''t gain anything from worrying about it, but if it is happening every frame you have a problem.

D3DPOOL_DEFAULT will decide where to put it, prefering to put it in video memory but putting it in system memory if it can't put it in video memory. Othe pools put it in system memory with varying optimizations to the video card (managed copies to the device memory when needed, systemmem doesn't go to the card very often). Usually default is quickest, managed is safest (doesn't need to be reset after a device loss), and systemmem is only good if you're doing a lot of CPU processing on the surface/buffer. It is up to you as the programmer to let D3D know which optimization technique it should use.

I don't know about DirectSound, sorry.

[edited by - Erzengeldeslichtes on February 1, 2004 2:34:28 PM]

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Original post by Erzengeldeslichtes
D3DPOOL_DEFAULT will decide where to put it, prefering to put it in video memory but putting it in system memory if it can''t put it in video memory. Othe pools put it in system memory with varying optimizations to the video card (managed copies to the device memory when needed, systemmem doesn''t go to the card very often). Usually default is quickest, managed is safest (doesn''t need to be reset after a device loss), and systemmem is only good if you''re doing a lot of CPU processing on the surface/buffer. It is up to you as the programmer to let D3D know which optimization technique it should use.

I don''t know about DirectSound, sorry.

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Sigh...

Default will always try to put it in the hardware. Managed keeps a copy in software to do modifications to and then sends that to the hardware on updates or resets. You still have to call reset on a lost device even with managed, it''s just easier to handle. Managed also watches for some redundant state checks. Use default if you are very careful and you need that extra few clock cycles, otherwise it''s more trouble than it''s worth. Software keeps everything in software and sends it to the video card every time it is used. Aka it is very slow, and should only be used if you are modifying something like a texture almost every frame.

Perhaps I should have said doesn''t need to be reloaded? Thanks for the info that redundant states are watched by managed. Otherwise everything you said is essentially the same as mine. (Default = fastest, managed = safest, systemmem = CPU based) Hardly worthy of a sigh.