New iMac 27": Performance Lags

A rather annoying problem has been reported with the new iMac 27" (and only this model). The system seems to be using a large part of the available CPU load for an unknown function without any obvious reason. While a flash player was originally suspected, it could only be a way to identify the already existing symptom: excessive CPU request.
The problem might be indirectly linked to Airport, as cycling Airport activity (turning your wireless network on and off) could help to stop temporary the performance lag. Some users suspect a problem with the PCI Express channels. Indeed, the Airpot card as well as some component of the GPU make use of the PCI Express. So, it could well be a issue with addressing or some bottleneck events at this stage due to management problem at the chipset level.
This is not the first time that Apple face a problem with a new iMac, and in the past it almost always affected the high-end model or with the largest display. It will most likely be fixed by a EFI update or the release of new drivers in the forthcoming Mac OS X 10.6.2 update as beta version evaluations seems to be completed.