Graphics: A substantial bump

There are three new GPUs in the new iMacs: the AMD Radeon 6750M, 6770M, and 6970M. Unlike their desktop counterparts, the 6750M and 6770M are true 6000-series GPUs, and not just rebadges of the 5750 and 5770 (though, as always, making direct comparisons between desktop and mobile parts remains difficult).

On the entry-level iMac, the 256MB Mobility Radeon HD 4670 has been replaced by a 512MB Radeon HD 6750M – you get double the graphics memory, a switch from GDDR3 to GDDR5, DirectX 11, OpenGL 4.1, and OpenCL 1.1, as well as Eyefinity+ and UVD3 and the other Radeon 6000-series niceties. For gamers, this should substantially improve performance, especially if you’re interested in trying to game at the 21.5” iMac’s native 1920x1080 resolution.

Moving up the chain to higher-end models, the 512MB 6770M isn’t as big a step up from the previous generation’s 512MB Mobility Radeon 5670 – like the desktop cards, the 6770M is essentially a higher-clocked and gently tweaked revision of its previous-generation counterpart, and higher clocks are likewise all that separate it from the 6750M. You pick up UVD3, but a lot of the on-paper specs are the same. It’s still an improvement over the previous generation, but compared to the low end and (as we’ll see) the high end, it’s not as substantial.

And, finally, we’ve arrived at the high end 27” iMac, which gets a 1GB 6970M to replace last year’s 1GB Mobility Radeon 5750. The 5750 is more or less a midrange graphics part – the mobility 5600 and 5700 series GPUs all share the same core, codenamed Madison – but the 6970M is a true high-end part, complete with a 256-bit memory bus (compared to a 128-bit bus for the 5750) and more than double the shaders (960 in the 6970 versus 400 in the 5750). This, again, will drastically improve the new iMac’s utility as a gaming machine – the 6970M is much more capable of driving the 27” iMac’s 2560x1440 pixel display. Update: Further research has revealed that the 5750 that shipped in last year's iMac was in fact a rebadged member of the mobility 5800 series using the "Broadway" core instead of the "Madison" core used in Mobility 5600 and 5700 parts. The 5800 series has 800 shaders and not 400, so while the bump in the new 2011 iMac is still a decent one, it's not as monumental as previously reported.

For the 27” models with two Thunderbolt ports, the 6000-series GPUs will also enable the use of three displays simultaneously, which will be handy for the Final Cut and Photoshop junkies who often invest in the higher-end iMacs.


The last thing I want to talk about is the subtle factor looming over these refreshed computers: Lion.

OS X 10.7 is supposed to bring a lot of iOS features “back to the Mac” when it releases this summer, and since these Sandy Bridge Macs are going to be the first computers the new OS ships on, we’re seeing some preparation for it on the hardware end.

To drive the iOS inspired touch enabled features, each new iMac can come bundled with either the touch-enabled Magic Mouse or the Magic Trackpad at no extra cost (it’s your choice – the Magic Mouse is the default option). The vanilla Apple Mouse is still a selectable option, but will save you no money compared to its touch-enabled counterparts, which are more expensive at retail.

Apple is also beginning to push SSDs in its laptops to replicate the quick boot and shutdown times of iOS, and we’re beginning to see that in the new iMacs – while none of the computers include an SSD by default, you can configure all but the entry level to include a 256GB SSD as either the primary hard drive or a secondary drive. Characteristically, Apple hasn’t posted anything about the manufacturer of this drive or its controller – Apple uses Toshiba SSDs in the Sandy Bridge MacBook Pros, and recently switched to Samsung SSDs for the MacBook Airs, but there’s really no telling exactly what these iMacs are packing until it’s in your hands.

To replace the mechanical hard drive with a 256GB SSD costs a whopping $500 ($600 to get the SSD and keep the mechanical hard drive as well), though that’s not too far above the market price for an SSD at this capacity. Also note that, at this point, TRIM only seems to be enabled in OS X for SSDs direct from Apple – even if you can put in an SSD as an aftermarket upgrade, you may not be as satisfied with its performance. This may change in Lion, but we have no solid evidence to that effect.


With this refresh, Apple has done what Apple typically does: offer faster hardware in a similar physical package while maintaining price points across the board. Quad core processors and beefier dedicated GPUs make these better buys, relatively speaking, than last year’s models, but the iMac is still the iMac: a midrange-to-high-performance all-in-one with a high-quality display. Today’s upgrades do nothing to change the iMac lineup on a fundamental level.

That is to say, if you were in the market for an iMac already, congratulations! Today’s iMac is faster and more capable than yesterday’s iMac on all fronts. If an iMac isn’t what would best suit your purposes, though, today’s update won’t do much to change your mind unless you were looking for better gaming performance on the low and high ends.

For more about the nitty-gritty on the new iMac's performance and internals, keep an eye out for our in-depth review in the coming weeks.

Specs and CPUs
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  • mianmian - Tuesday, May 3, 2011 - link

    It can.
  • Lonyo - Tuesday, May 3, 2011 - link

    No negative comments about the pathetic 1TB HDD that ships on a $2000 computer?
  • Guspaz - Wednesday, May 4, 2011 - link

    What's pathetic about it? There aren't any larger 2.5" drives out there, that's as big as they get.
  • Wurmer - Tuesday, May 3, 2011 - link

    You are correct by saying that no one buys a Mac for the specs. I use both Mac and PC and just bought a new rig similar to yours. I also use a mac book and and IPad that I very much like. I fine that those product each satisfied different needs. Next year maybe, I'd like to get and IMac but I am not completely sure yet. I am not arguing against what you said but there something that many people take out of the equation and it's the screesn included in the iMac. A 27'' of that quality cost a pretty penny, I am not current with actual prices but I guess that something around 800-1000 is pretty much in the ball park. I am not a fan of Apple but I like their products.

    Anyways, that said, those changes are welcome but I'd have liked more up to date hardware. USB 3 and eSata are pretty much necessary with the huge HHD capacity available to use for storage...
  • rs2 - Tuesday, May 3, 2011 - link

    A company as large as Apple hasn't worked out how to deploy new products into their online store without bringing the entire site down in the process? Epic fail.
  • ggathagan - Tuesday, May 3, 2011 - link

    I would suggest that they do that on purpose to add a little drama to the roll-out event.
    It's the online equivalent of standing in line for the new iPhone at the Apple store.
  • Exodite - Tuesday, May 3, 2011 - link

    Am I to understand that the connector is exclusive to Apple until 2012? As in no other company may license or make use of it until then?

    I must have missed that part in the Thunderbolt article, or at the very least glossed it over.

    Don't get me wrong, for obvious reasons I'm all but impressed with Thunderbolt but talk about making sure it'll be another Firewire or mini-DP.
  • mianmian - Tuesday, May 3, 2011 - link

    I do not think Intel would allow Apple using it exclusively. With the large base of USB devices, I think only Apple "dare" to use thunderbolt instead of USB3.0.
  • KoolAidMan1 - Tuesday, May 3, 2011 - link

    Thunderbolt is not exclusive to Apple. According to Intel it is at the discretion of PC builders as to when they implement it. Hopefully they will show up in PCs and motherboards later this year.
  • Exodite - Wednesday, May 4, 2011 - link

    I hope that's true, the comments in the article made me rather wary.

    Keeping an entirely unproven connector technology exclusive to one vendor would be an excellent way to nip it in the bud, so to speak.

    Not that I expect PC motherboard vendors to jump at the chance to implement it, seeing as it requires extra hardware and eats up 4 PCIe lanes. The latter you're hard-pressed to find available for love or money.

    I'd probably be less surprised to see it adopted on graphics cards than I would motherboards.

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