Our iMac review included a 3.06GHz Core 2 Duo chip inside, but we received the top-of-the-line iMac housing the more promising 2.8GHz Core i7 processor. Do more cores make up for lower clock speeds? Yes. Often 2X to 3X.

The Basic Differences in Chips

First off, I should note that the Core i7 chip has what Intel calls a “turbo mode.” That is, when it’s not utilizing all of its cores, it can dynamically overclock itself up to 3.4GHz on whatever single core is in use. It can, as shown in this video, work in steps. So you get the turbo benefit when using some of the four cores in this iMac’s chip, but you also get it when all cores are being partially used. For example, if four cores are running but only at a fraction of their total capacity (less then 100%), the cores can use that electrical/thermal overhead to overclock to varying degrees. This should theoretically make up for the difference between the two-core 3.06GHz chip and the hyperthreaded quad core chip at a base of 2.8GHz.

The other thing to realize about these newer Core i7 chips are that they have no northbridge—or bus—between the memory and CPU. The memory controller is built right into the processor, and there’s a new tech called QuickPath interconnect which connects the cores in a point-to-point architecture. Core i7 supports triple-channel memory (which would use three banks at once), but this iMac only came loaded with two banks of RAM filled. Like our other iMac, that’s a 2GB + 2GB arrangement.

Matt explains more about i7 here. (And yes, there are differences between i7 and i5, besides clock speed.)

*Note that this machine also had a faster ATI Radeon 4850 video card with 512MB of RAM (versus the 4670 card in the other iMac) which may have impacted performance in several apps. I have no idea which of these apps uses the GPU to accelerate its tasks under Snow Leopard. (For example, Preview may use it to help render JPGs faster, or it may not. Apple could not tell me. In Adobe After Effects, the Radeon series of cards apparently is not supported for OpenCL acceleration. )

Performance with Multithreaded Apps

In short, any task we tried that expressly was written to either a) take advantage of multiple cores, or, b) take advantage of multiple cores through Snow Leopard’s multicore middleware, Grand Central Dispatch, were 2 to 3 times faster. (More on that here.) These results include:

• 64-bit versions of Geekbench, which focus on CPU and memory tests.
• Adobe After Effects benchmarks
• Opening 20 images of Tokyo Tower that are 2000×2000 pixels and 35MB each.

Impressive stuff, but honestly, those tests were kind of uninteresting to me. I mean, those tests don’t really have any correlation to my daily computing use. So on a whim, after benchmarking, I tested Handbrake, the DVD ripping software I love. It, too, was freaking fast.

I know the app is multithreaded, but I did not know what level of optimization it was written for. I was blown away by a 3x speed multiplier with the i7. On the Core i7 iMac, it took 43 minutes to rip a DVD, Storm Riders, a surfing film from the ’70s featuring Gerry Lopez (my favorite) and others. On the Core 2 Duo machine, it took 147 minutes! I know this is basically a DVD read test coupled with decoding and video conversion, but the results have me excited because this is a real task that takes my computer a long time to do, performed by a program that hasn’t been revised in a year.

Performance With Single-Core Optimized Apps (Otherwise Known as Reality)

Unfortunately, there are still very few applications that take advantage of multiple cores directly or via Snow Leopard’s GCD, not even video-based, let alone general purpose computing.

Photoshop CS4 on the Mac, which is not set up to handle multicore processors, showed almost less than a 3% improvement using the Driver Heaven benchmark. Basic tasks, like booting and shutdown, saw virtually none. Playing the 1080p Quicktime trailer of Avatar consistently showed that the i7 was using 3% less of its total CPU than the Core2Duo, but I wonder if that’s a result of the faster graphics card kicking in using CoreCL. Xbench, the old program that does a more comprehensive job of benchmarking a system from disks to processors, showed almost no difference.

I think Xbench, which hasn’t been updated in years, is a solid benchmark for that old program that you depend on but has been long abandoned or at least ignored by its developer.

These scores, again, are in relation to the top line 3.06GHz Core 2 Duo iMac we tested. Some benchmarks have come in from the web comparing the i7 to the i5. Here’s one that claims a 30% jump using Geekbench. Now we know Geekbench likes and does well with more cores and is a synthetic CPU test. But if the i5 is 30% slower, and the i7 pulls even with the 3.06 GHz Core 2 Duo chip in single threaded activity—most day to day activity—does that mean the i5 is slower than the cheaper Core 2 Duo? Maybe. Probably not 30%, since Geekbench is strictly CPU/memory and likes more cores, and this stuff does not translate so literally in the real world. But we can assume the i5 will have 30% less jump from the top tier Core 2 Duos, translating into a mere 1.3X to 2X speed increase from last gen chips on programs that like cores.

Value

For the most part, in our review, I said that you should stick to the preconfigured options, upgrading to Apple’s next recommended config before considering upgrades to the lower tier models. How does that advice change now that we’ve seen the i7? I don’t know! I guess it depends if you’re a betting man. If you think programs for Snow Leopard using GCD are coming, paying $200 to $500 bucks more from the top line Core 2 Duo chip for an i5 or i7 might make sense. The probability of you getting programs that can use those extra cores goes up if you are a graphics or video professional who expects to see support from Adobe, Apple, etc. (Apple already claims big jumps in Aperture that we weren’t able to test.) Or if you rip a lot of DVDs! The rest of you? The Core 2 Duo stuff could be fine for today and fine for tomorrow. But the Core i7 is not worse for today and will definitely be faster tomorrow. It just costs more.

Me personally? I’d opt for the Core i7. I just might wait til the new iMacs refresh a bump and the i7 is cheaper and part of a standard build. But I’m patient like that.

[iMac Review]

Continue reading Dual Electronics XML8110 in-dash iPhone dock announced

Filed under: Transportation

Dual Electronics XML8110 in-dash iPhone dock announced originally appeared on Engadget on Wed, 18 Nov 2009 13:54:00 EST. Please see our terms for use of feeds.

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Before we can test the Garmin Nuvi 1690, we have to unbox it. Check out the photos and see what’s in the box. pOriginally posted at a href=”http://reviews.cnet.com/8301-13746_7-10400668-48.html” class=”origPostedBlog”The Car Tech blog/a/p

AT&T would like to sell you a computer to go along with your phone.

But don’t look for any really good deals. The carrier will be selling netbooks on contract, but the purchase price will remain close to what you’d pay for a netbook without a contract.

Unlike in Europe, where some netbooks are nearly free with data plans, AT&T says it does not intend to fully subsidize netbooks in the United States. Instead, it will introduce session-based prices, day-pass and weekly data-access plans for customers who prefer to buy their netbooks at full price. At the same time, it will continue partially subsidizing netbooks when combined with a two-year wireless-data contract.

“We want to give customers a choice in how they use their netbook,” says Glenn Lurie, president of AT&T emerging devices. “But free netbooks from AT&T on contract is not part of the plan.”

Netbooks have become one of the fastest-growing categories in the PC industry. They are largely used for social networking, surfing the internet and checking e-mail, so telecom carriers such as AT&T bet they can piggyback on netbooks to attract more customers to their data plans. AT&T, for instance, is offering netbooks with two-year data contracts, similar to how it sells cellphones.

Currently AT&T offers netbooks such as the newly launched Nokia Booklet 3G, Samsung GoTM Netbook and Acer Aspire One.

It’s a strategy that has worked in Europe. In Germany, for instance, T-Mobile launched the Acer netbook for 1 euro plus a 35-euro-a-month, two-year data contract.

But U.S. consumers are unlikely to find such deals. Take the Dell Inspiron Mini 10 that AT&T offers for $150 with a two-year contract. Customers can pay $35 a month for 200 MB or $60 a month for a 5-GB data limit. That means a total cost of ownership of $990 to $1,590 over two years. By contrast, you can buy the same netbook without a data contract for $450 on Dell’s website.

That comparison may not entirely be accurate, says Lurie. “This is not just about having a computer, it’s about having a mobile computing device,” he says.

For instance, subscribers who pay $35 a month or $60 a month on a two-year contract will also get free access to AT&T’s 20,000 Wi-Fi hotspots nationwide.

That’s a deal that daily or weekly pass customers won’t have, says Lurie.

See Also:

• The Netbook Effect: How Cheap Little Laptops Hit the Big Time
• Nokia Reveals Netbook Pricing, Introduces New Handsets
• AT&T Offers Netbooks With Small Subsidy, Fat Contract
• The Next Netbook Trend: Cellphone-Like Contract Deals
  

Photo: Dell netbook Jon Snyder/Wired.com

Welcome to the Engadget Holiday Gift Guide! The team here is well aware of the heartbreaking difficulties of the seasonal shopping experience, and we want to help you sort through the trash and come up with the treasures this year. Below is today’s bevy of hand curated picks, and you can head back to the Gift Guide hub to see the rest of the product guides as they’re added throughout the holiday season.

Look, we all know “that guy / gal.” The one that never seems to end up at a meeting place on time, who incidentally is the same one that always gets tied up at the local fuel station asking for “directions.” We’ve always heard that true friends don’t let friends drive sans a robotic navigator, and if your BFF is still traversing the highways without any sort of GPS device on board, it’s time for that situation to be remedied. There’s a whole slew of options out there, so we’ll be breaking ’em down as best we can based on how much dough you’re willing to spend. Whatever you decide, just make sure you get one with the maps of your own country; after all, you wouldn’t want that special someone to end up like this guy, right? Read on!

Continue reading Engadget’s Holiday Gift Guide: GPS devices

Filed under: GPS

Engadget’s Holiday Gift Guide: GPS devices originally appeared on Engadget on Wed, 18 Nov 2009 13:10:00 EST. Please see our terms for use of feeds.

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