The most obvious change in Apple's new all in one computer range is to the iMac screen. Both the 21.5- and 27-inch screens are made with high definition video in mind.

Like on many HDTVs, the black border around the new iMac's screen reaches out to the very edge. The aluminium border that surrounded the screen in the previous iMac is gone.

21.5-inch and 27-inch Apple iMac

This gives the effect of the screen being bigger than it really is. To the chagrin of many, there is no matt screen option. Glossy is your only choice.

While the 21.5-inch iMac isn't much bigger than the previous 20-inch iMac on paper, sitting side by side, the 21.5-inch iMac seems huge.

The 27-inch iMac is gloriously big, but one Macworld editor said it might even be too big as a desktop Mac.

The iMac now uses an all aluminium case, whereas the previous iMac has a black plastic back. If you look very closely, you can see a seam between the lower aluminium front panel and the side of the case.

The power button is flush with the back panel and is also aluminium, so it feels like the rest of the back.

If you're reaching around the back from the front of the iMac, it's not as easy to find as the power button on the old iMac, which had a concave button that had a different texture than the back panel.

27-inch Apple iMac

Apple says that the iMac screens are LED-backlit widescreen TFT active-matrix LCDs with in-plane switching technology, and can display millions of colours at all resolutions.

In the past, Apple has used 6-bit displays on its 20-inch iMacs and 8-bit displays on its larger-sized iMacs. Apple doesn't specify the bit depth on its iMac website. I'm waiting to hear back from Apple about this.

In-plane switching is supposed to help flat-panel displays maintain image quality at any angle, and this seems to help with the new iMacs.

I didn't notice any colour shifting or loss of image quality when viewing at extreme angles. On the previous iMacs, there was a noticeable colour shift. On the old 20-inch iMac, it didn't take much of an angle to see the colour shifting.

As for performance, the iMacs felt snappy while opening and closing windows, and startup was fast, but I didn't get a chance to run any formal benchmarks. The iMacs will be in our lab for speed testing. Keep an eye out for benchmark results coming soon.

The new iMacs come with the new Magic Mouse.

iMac processors

The 21.5-inch and 27-inch models, one of the following:

  • 3.06GHz Intel Core 2 Duo processor with 3MB shared L2 cache.
  • 3.33GHz Intel Core 2 Duo processor with 6MB shared L2 cache.

The 27-inch models only, one of the following:

  • 2.66GHz quad-core Intel Core i5 processor with 8MB shared L3 cache; Turbo Boost dynamic performance up to 3.2GHz.
  • 2.8GHz quad-core Intel Core i7 processor with 8MB shared L3 cache; Turbo Boost dynamic performance up to 3.46GHz; Hyper-Threading for up to eight virtual cores.

iMac memory

4GB (two 2GB SO-DIMMs) of 1,066MHz DDR3 SDRAM; four SO-DIMM slots support up to 16GB.

iMac graphics

The 21.5-inch models feature one of the following: NVIDIA GeForce 9400M graphics processor with 256MB of DDR3 SDRAM shared with main memory, or ATI Radeon HD 4670 graphics processor with 256MB of GDDR3 memory.

The 27-inch model with dual-core processor feature one of the following: ATI Radeon HD 4670 graphics processor with 256MB of GDDR3 memory, or ATI Radeon HD 4850 graphics processor with 512MB of GDDR3 memory.

The 27-inch model with quad-core processor features an ATI Radeon HD 4850 graphics processor with 512MB of GDDR3 memory.

iMac connections and expansion

  • One FireWire 800 port; 7 watts
  • Four USB 2.0 ports
  • SD card slot

OUR VERDICT

The new iMacs introduce the most drastic changes to Apple's all in one aluminum design since the metal iMac was introduced a little over two years ago. The new design lends itself more towards use as central part of a home entertainment centre.