When did Apple switch to intel

Because PowerPC was not able to give Apple what it needed.

Sorry read that was why. 2006 was when they switched from PowerPC to Intel.

2006

There was no G5 chip at that time that was capable of being used in a laptop type Mac without severe heat and battery limitations.

Apple, not wanting to lose momentum in their share of the portable market decided that a complete shift to the Intel CPU family was their only prospect and they did so in 2006.

They included a "translator" which they called Rosetta (and licensed from a third party) in OS X from Tiger through Snow Leopard, so that all Mac users could continue to use their PowerPC software seemlessly, while users and publishers could update their titles to Intel versions.

the announcement was in 2005, the first Macs with the Intel chips appeared early the following year. This was also released a year after Tiger, and one of the updates was designed for both platforms (I think 10.4.3 or so).

As MichaelLAX mentioned the reason the G5 CPU was only engineered for desktops (and servers.) They maxed out the G4s for the PowerBooks as much as they could, but they could go so far. Also Apple introduced Boot Camp where someone could install a licensed copy of Windows onto their Macs and boot seamlessly by hitting Option at startup. The latter was probably a great selling point to draw in new, never used Mac owners. This was around the time Apple was selling Macs in record numbers quarter by quarter.