The customised 27in machine’s 1TB Fusion Drive delivered
extremely fast read speeds of 407MB/sec and write speeds of 322.8MB/sec, and as
a result OS X felt very responsive in general use and when opening apps. With a
hard disk capable of decent transfer rates, it’s reasonable to expect
impressive performance even when the flash element gets full and the OS begins
to move your least-used files to the slower storage medium, although we’ll need
longer to test this. Keep in mind that maintaining a regular backup, preferably
via Time Machine to an external hard drive, is even more important when you
have two devices that could fail.
If you prefer the full-blown SSD option, Apple’s pricing
becomes an issue. These days a 256GB drive can be bought for under $182, but
Apple offers only a 768GB option on this iMac, and its $1,352 price tag is
prohibitive. More attractive and available only on the 27in, is a 3TB hard disk
option, at $156, which is also available as a Fusion Drive for $416. A catch
with this is that, as Apple acknowledges, a technical hurdle prevents you
installing Windows using OS X’s Boot Camp Assistant on drives larger than
2.2TB. Two canoes Software, maker of the Winclone utility, explains this issue
and how to work around it at bit.ly/l3ofNJL; it’s somewhat technical, but not
difficult.
There’s no SuperDrive for reading and writing optical discs
in any of the new iMacs. They’re just too thin at the edges. This leaves you
with the choice of adding Apple’s external DVD drive ($84.5) Ora third-party
unit (around $39), or exploring the various hacks that would enable you to
access Blu-ray storage, which is not supported at all by Apple.
The Intel Core processors in these iMacs are based on the
Ivy Bridge architecture, which is the direct replacement for the Sandy Bridge
type used in 2011 iMacs. Our review of the 21.5m models revealed a slight edge
over the previous models in CPU performance, and the 27in models follow suit.
New 27in iMac from
behind
In Cinebench’s software-based rendering tests, the 2.9GHz
Core i5model performed on a par with a 2011 3.4GHz Core i7 model in the single
core test. That’s impressive, since the 2011 Core i7 was a considerably more
expensive extra-cost option. With all cores active forCinebench’s multi-core
test, however, the older and faster Core i7 processor maintained a performance
margin of 25% thanks to its Hyper-threading technology, in which its four
physical cores operate as eight virtual cores. The Core i5 doesn’t allow this.
A more direct comparison can be made between the new 3.4GHz
Core i7 Ivy Bridge iMac and the 2011 Sandy Bridge configuration that it
effectively replaces. The newer processor delivered a 9% improvement in
Cinebench’s single core test. In the multi-core test, it increased its
performance margin slightly to 10% over the older iMac.
As with the 21.5m machines, it’s the new range’s graphics
processors that really push the Late 2012 models ahead of their predecessors,
and the most significant gains are at the high end.
The $1948.7 configuration’s GeForce GTX 660M delivered a
decent rendering speed of 40.2 frames per second in Cinebench’s OpenGL test. In
Portal 2, at medium settings and a resolution of 1600 x 900 pixels, it reached
a more than respectable 129.5fps. Merely raising the resolution to the
display’s native 2560 x 1400, however - bearing in mind that this is the
largest number of pixels you’ll see on the largest screen size commonly found
in the desktop computer market - reduced this to a still playable 53fps.
Our custom-build test iMac, on the other hand, was fitted
with the best GPU Apple offers: a GeForce GTX 680MX with 2GB RAM. This adds
$156 to the $2208.7 cost of the top standard specification. The performance of
this machine was also boosted by other factors, in particular its 3.4G Hz Core
i7 processor upgrade.
In Cinebench’s OpenGL test, the 680MX didn’t perform a great
deal better than the AMD Radeon 6970M that was the top GPU in the 2011 line-up:
it rendered at 44.9fps, compared to the older GPU’s 43.1fps. Benchmarks,
however, don’t always reflect real world performance. When we ran Portal 2 on
our default ‘medium’ settings, with the resolution at 1600 x 900 and without
anti-aliasing, the game ran at an astonishing 181.34fps. Bumping up the
resolution to the display’s native 2560 * 1440 pixels reduced this only to a
still ridiculous 151.8fps. When we raised all the settings to maximum,
including 8x anti-aliasing, the GPU still managed to pump out pictures at 129.1
frames per second -more than you could ever ask for completely smooth play.
If raw performance is what you need, then, especially for
GPU-intensive tasks, the higher 27in configuration upgraded to the 3.4GHz Core
i7 and 680MX is a great choice, and actually a little cheaper than its 2011
equivalent if, unlike us, you resist the Fusion Drive option. If you want to
spend less, the $2208.7 base configuration comes with a GeForce 675MX GPU which
will be faster than the $1948.7 option’s 660M, although Apple didn’t provide us
with this to test. What’s clear is that spending more as you move up the range
and through the build-to-order options does give you considerable benefits for
heavy tasks.
Arriving just over 18 months after the 2011 models, these
new iMacs won’t be an easy purchase to justify for owners of their immediate
predecessors. But the heart-stopping design makes it tempting, and at the top
end of the range you could get yourself a very noticeable performance increase
in GPU-intensive tasks, with the faster memory and CPUs giving at least a small
boost to all configurations and apps. Of the two sizes, the 27in iMac is now
clearly the better option if your budget permits, given the faster hard disks
and user-upgradable RAM.
If your current Mac is any older, the decision is an easy
one. Those 2011 iMacs showed big improvements over the machines they replaced,
so the cumulative gains are substantial. And if you don’t currently have a
desktop Mac at all, you now have the chance to invest in probably the most
desirable one since 1984.
Headphones
This 3.5mm jack still offers both analogue and optical
digital output and supports headset mics, but the only audio input now is via
USB
USB 3 and Thunderbolt
With four USB 3 ports and two Thunderbolt, fast storage is
easy to add
iMac 27-Inch Ports
SDXC Card
It’s really useful having a memory card slot round the back
of a giant machine, not
Ethernet
Yes, still here!
Tuce behind the iMac’s stand is a rectangular hatch with’ a
lid that pops off to reveal the four RAM slots, each able to take a module up
to 8GB
Maxing out the RAM ‘to 32GB will only cost you around $169
as a DlY upgrade, a hugely cost-effective, boost for creative pro tasks
Dual mics at the 7 top edge help OS X focus on your voice,
cutting background noise
The iMac’s stereo speakers, much beefier than before, point
downwards through these vents to bounce sound off your desktop
No change to ‘the keyboard and mouse options, but I you n no
longer add I an Apple Remote for red control over iTunes
