PCI Hack for Quartz Extreme not for everyone – Macitynet.it
Enabling the hack reported here to activate Quartz Extreme acceleration on macs with PCI cards decreases 3D acceleration performance.
That the 'manual' modification of the settings can cause significant collateral problems is demonstrated by PCI Extreme, one of the sites that had disclosed the information and a utility capable of enabling Quartz Extreme.
According to the site, the hack increases the speed in 'light' tasks by 5/10%, such as using the program interface, surfing the Internet and writing, but it also reduces performance by 50% in situations in which where the graphics acceleration card performs primary tasks. These include video encoding and decoding, especially of DVDs. Also affected are programs that use QuickTime like games.
The explanation apparently and logically would be traced back to the fact that by 'diverting' the management of the GUI graphics and the interface to the PCI bus, this takes on tasks that burden its operation by saturating the available bandwidth.
Those who intend to use Quartz Extreme also on cards for which Apple has not foreseen it would therefore do well to point out that for a slight advantage in non-crucial tasks, they may have to deal with very serious problems in reading DVD and in other applications with unpleasant consequences such as a drop in the number of frames and loss of audio and video synchronization.