use the mac book pro 2009 osx 10.8.5 with cubase 7.06 halion 4, on the street, on the train, I compose, I can guarantee that your internal sound card and not one problem, even at lower latencies.
obvious warms up a bit the mac, it consumes more battery, but I do not see spike …
advice …
8 gb ram,
cubase 32 bit
install the free application memory to control consumption.
install smc fan controll is also free, to control the temperature of the cpu …
ciaoooo