I run some tests on my new MacBook Pro 17" 2x2.8Ghz, equipped with Geforce 9400M GT IGP (MCP79) w/ 256MB shared DDR3 and Geforce 9600M GT w/ 512MB video ram.
In maximum battery life mode, only the 9400M IGP is running and is recognized, as expected.
But in Maximal Performance mode, if you trust Apple, only the GeForce 9600M GT may be recognized and used.
It is false, in Maximal Performance mode, you have both recognized, 9600M GT as device 0 and 9400M GT as device 1, deviceQuery recognize both, and you could test each one with bandwidthTest -device=0 or bandwidthTest -device=1
Anyway a great news for developpers that may optimize for both IGP and real GPU, and try Mapped Pinned Memory on 9400M, without switching mode endlessly, loosing their session!!! :-)
bandwidth.1.txt (413 Bytes)
bandwidth.0.txt (417 Bytes)
deviceQuery.txt (2.72 KB)