iMac 20in 1.25GHz review

The 17in iMac now has a big brother.

Believe it or not, Apple has launched a version of the well-known 'anglepoise' iMac with a 20in flat-screen display. If you didn't see one at the recent Mac Expo, you'd be forgiven for assuming the effect would be somewhat unbalanced. However, this is far from the truth. Rather than the top-heavy product we expected, the new iMac feels like a well conceived, well balanced machine. The 20in display is the same 1680 x 1050 pixel model as the one used in Apple's 20in Cinema Display, but without as much of the outer frame structure. It balances well on the central chrome swing-arm. Although we had wondered how it would manage with the extra weight, the one-finger tilt and swivel works as well with this as with the original 15in iMac G4 screen.

Apple describes the new iMac as a 'boundary product', one it feels will appeal to both high-end consumers and general professional users. After trying it for a while we have to agree: it's well suited to professional creative work, and would look absolutely stunning in the home.

Beating hertz

The performance of the 20in iMac is, not surprisingly, essentially identical to the 17in model. Both machines have a 1.25GHz G4 processor, 256Mb of RAM, an 80Gb hard drive, and an Nvidia GeForce FX 5200 Ultra graphics card with 64Mb of video memory. These specifications won't exactly threaten the Power Mac G5 range, but are more than reasonable in most respects.

Of course, if you plan to use this Mac for serious Photoshop work, you'd be well advised to add more RAM. The 256Mb fitted as standard is fine for general-purpose work, but Photoshop and similar RAM-hungry applications are happier with more - add at least 256Mb to the single user-accessible memory slot to give them the room they need.

Our disk speed results for the Ultra ATA drive showed a healthy 57Mb/sec average throughput for sustained data transfer, which is more than enough to cope with just about anything.

The graphics hardware also performed as well as we expected. Both 2D redraw speeds (the operations that go on all the time with everyday applications) and processor-intensive 3D calculation performance results were pleasing. The only aspect that proved different was with testing raw graphics performance at the higher native screen resolution. As more display data has to be juggled - 1680 x 1050 pixels as opposed to the 17in model's 1440 x 900 pixels - this has a slight impact on absolute performance figures. However, there were no significant differences when the MacUser Labs benchmark 1024 x 768 settings were used.

Into the Bluetooth

There's one thing about this Mac that disappoints us, although it's simple enough to fix if understood in time. The lack of a bundled AirPort card isn't yet significant in a desktop Mac, but the absence of a Bluetooth module included as standard in this flagship model seems terribly strange.

Apple has been putting much effort into evangelising Bluetooth, but this technology still isn't built into any desktop Mac as standard. Worse, if Bluetooth isn't specified at the time of purchase, you can't add it later except as a plug-in USB device. Internal Bluetooth support simply isn't a retro-fit option, even by qualified engineers.

We'd also like to see both memory slots made available to end users. As it stands at the moment, the iMac has one slot that you can get at, but the other remains locked away behind an inner panel that can't be removed without engineering know-how, not to mention specialist tools. If you buy the iMac and specify that you want 512Mb of RAM, be sure to insist on this being with a single, 512Mb memory card. Otherwise, you'll be given a 256Mb memory card in each slot, which means no spare slot for further expansion and no easy way to move up to the maximum 1Gb of RAM in the future.