> This technique, which Apple dubbed "Quartz Extreme" requires > a GPU with certain features and performance. Further, it only really > works well if the machine use the AGP, rather than PCI, to connect > graphics to computer. Apple don't officially support QE via PCI, and > although there are hacks to turn it on, it can overload a PCI bus so > severely that it causes other problems like random freezes.
QE feels a lot like a first draft of a solution. It's a clever design, but the implementation is very sketchy. The problem is that instead of treating the GPU memory as a writable cache Apple retains the primary copy of the window in main memory. Instead of writing the copy in the cache back when more GPU memory is needed, extending the memory hierarchy that UNIX already maintains towards the GPU, they repeatedly render and copy textures over and over again. With a properly designed memory hierarchy, QE would require less bandwidth rather than more. If they integrated the program into the memory hierarchy instead of retaining bitmaps that the program can quickly re-render, the way Quickdraw and X11 and Windows do, A program that used OpenGL rendering directly would never need to have a bitmap in main memory, and memory use would go down (again) and performance go up. Hopefully, as Apple has time to develop Quartz further, they will do this and QE will accelerate even programs like Quicktime Player that must re-render and re-transmit every frame and right now suffer badly from QE on a PCI bus. -- Unsupported OS X is sponsored by <http://lowendmac.com/> Support Low End Mac <http://lowendmac.com/lists/support.html> Unsupported OS X list info <http://lowendmac.com/lists/unsupported.html> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive <http://www.mail-archive.com/unsupportedosx%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
