The new super-thin 21.5-inch iMac is quite a view and getting inside the new Apple desktop is most definitely an engineering marvel, as proved by the latest discovery of teardown specialist iFixit.

The whole iMac shell is 'crackable' indeed but according to iFixit experts, Apple should have included a warning label on its latest all-in-one that says "open up at your own risk." There was no turning back when poking inside the deep recesses of this Apple computer.

It may be that adhesives were holding the iMac's housing but they're powerful enough for the uninitiated and trying to pry open the gadget would most likely ruin it. Experts from iFixit sweated so much in tearing apart the machine that they gave it a reparability rating of only three.

The tech site gauges devices' self-repair features when taking them apart with 10 being the highest score and so far Apple has played its reputation to the hilt, iFixit said, as if declaring that ordinary mortals cannot just mess with our creations.

And if you are the kind who normally tinker with things you own, the iMac is a big disappointment, which actually proved the tech titan's notice that attempts to upgrade any iMac components is next to impossible.

Any such try would require taking apart "most of the iMac just to gain access," iFixit said, adding Apple is so convinced that the 8GB onboard memory with the wafer-thin computer is more than enough.

Of course, the iMac RAM can be pushed up but Apple wants its technicians to do the trick at a cost of between $US200 and $US600, which Computerworld said is quite sky-high considering users with advance skills could perform the same task with so much cash to spare.

In short, almost every single component placement in the iMac's logic board has seen 'improvements' in terms of protecting them from unauthorised scrutiny, iFixit said, effectively highlighting what Apple engineering is all about.

But not everything inside the Apple machine is a surprise as iFixit 'met' the usual suspects on its inch-by-inch effort to reveal what are hidden inside the iMac.

Intel was there and so was NVIDIA, supplying the chips that power the computer, while LG was found as the responsible supplier for the iMac's LCD, underscoring the fact that Samsung is gradually fading away from Apple's supply chain.

But the most notable iFixit finding is that some of these iMacs may have been put together within the borders of the United States, CNET reported on Sunday.

Right at the back of the very iMac that iFixit experts laboriously opened up read the familiar Apple declaration that says "Designed by Apple in California, Assembled in (not in China) U.S.A."

Now that is quite a surprise, as far as the U.S. government is concerned.