Intel Core i7-620M £250
21st Jan 2010 | 12:38
Intel's CPU-GPU fusion chip comes to laptops near you
Intel Core i7-620M: Overview
Combining CPU and graphics functionality in a single so-called 'fusion' chip is the shape of things to come. So say both Intel and AMD, its main rival in the computer chip business.
That doesn't necessarily mean it's a good thing, however, as our first taste of a fusion processor in desktop trim recently proved.
But could the laptop version of Intel's new fusion processor, reviewed here in Core i7-620M form, have the makings of a mobile masterpiece?
Certainly, this chip cranks out some eye-popping raw performance numbers given their modest dual-core configuration.
The problem on the desktop is that the inclusion of a relatively weedy integrated graphics processor does little but compromise the thermal footprint of what would otherwise be a stunning little dual-core processor.
Make it mobile
However, for a mobile PC, the idea of reducing the chip count and thereby system complexity makes much more sense. Smaller, simpler motherboards and fewer power-hungry chips is always a good idea for a laptop.
Likewise, graphics performance tends to be less critical, particularly when running on battery power. So there's real value in stuffing a graphics core in with the CPU if it delivers physical and power consumption efficiencies.
All of which means the whole idea of CPU-GPU fusion processors is much more of a goer for mobile.
Intel Core i7-620M: Technical details
Enter, therefore, Intel's Arrandale processor. That's the codename for the mobile version of essentially the same CPU-GPU combination found in desktop Core i3-500 and i5-600 processors.
Except in mobile format, Intel will be applying the full whammy of Core i3, i5 and i7 Mobile monikers depending on differentiators such as clock speeds and cache memory.
Two chips in one
What all Arrandale chips share is a two-chip construction under the hood. Just like the Clarkdale desktop version, the first chip is a 32nm item housing a pair of execution cores and a helping of cache memory.
The second uses Intel's older 45nm transistors and packs the memory controller, PCI Express and that controversial graphics core.
Our review model is the high-end Core i7-620M, a 2.66GHz chip with 4MB of cache memory that clocks up to a maximum of 3.33GHz in Turbo mode (we also have a review of the closely related but more affordable Core i5-540M).
Serving as a yardstick we have an example of Intel's existing Core 2 Duo mobile processor in 2.4GHz trim. Not the fastest Core 2 Duo available, therefore, and not a like-for-like comparison in terms of operating frequencies.
Despite that, the advantage the new processors carve out is still stunning. The 620M is twice as fast in our HD video encoding and professional rendering benchmarks. Memory bandwidth has likewise ballooned from under 6GB per second to nearly 10GB per second.
Shift the emphasis to high-definition video decoding and the new chip is just as impressive. A 2.4GHz Core 2 struggles to cope with the BBC's 720p iPlayer streaming video, for instance, dropping frames and running at around 90 to 95 per cent CPU time.
Intel's new mobile machine shrugs that task off in return for just 40 to 50 per cent of available CPU resources. Stunning.
If you're wondering how this is possible, it's down to features such as HyperThreading that come with the Nehalem-class architecture which underpins Intel's latest mobile chips. It all adds up to what Intel rightfully claims is quad-core rivaling performance from a dual-core processor.
Intel Core i7-620M: Performance
If that video decoding performance wasn't impressive enough, our early testing indicates that Intel has manged to deliver this massive increase in performance for pretty much the same power consumption.
On the one hand, that means you can go with one of these high performance Arrandale chips as reviewed here and enjoy quad-core class performance for the same sort of battery life you get with today's high performance Core 2 laptops.
Or you can plump for one of the new low-voltage Arrandale processors and enjoy performance similar to a high-end Core 2 laptop but with much improved battery life. You can find a full listing of all the new Arrandale-based CPU models here http://www.intel.com/products/processor/index.htm.
As for the integrated graphics core, it's a big improvement over previous efforts.
Typically it delivers a doubling of frames rates in most games. Problem is, double of something awful is still pretty mediocre. This new core still struggles to cope with even older games such as Call of Duty 4, for example. It' simply not viable for gaming.
There's better news, however, on the 2D video decode front. On paper, Intel has raised its game to near level pegging with AMD and Nvidia, thanks to full hardware support for the full gambit of modern HD codecs, including VC-1, AVC and MPEG2.
Our early testing suggests Intel has done a decent job with its 2D video acceleration of locally stored content.
For now, however, there's one key question that remains unanswered - will it get the job done for streaming online Flash video?
In theory, it should do. Moreover, Adobe recently released a beta version of the Flash player with GPU acceleration support. But currently it's only optimised for Nvidia graphics. Until the final version is released, we'll have to wait and see just how good a job Intel has done.
All of which means Intel's new mobile monster has just one major weakness - branding.
Hard to believe, but with the release of these new mobile processors, Intel's new branding scheme has become even more catastrophically confusing than before.
The labels Core i3, i5 and i7 have literally ceased to bear any relationship to the actual hardware you are buying.
For the record, we've therefore officially given up trying to understand what any of it means or attempting to explain the logic of it. Because there is none.
We can only assume Intel is hoping for a similar effect on its customers. The better to confuse the crap out of them to the point of blind panic buying, presumably. We jest, of course, but only just.
Intel Core i7-620M: Verdict
We're happy to report that with the arrival of this new mobile processor, Intel's CPU-GPU fusion architecture has really found its niche.
On the desktop, fusion processors offer few advantages and several disadvantages. But in notebooks, putting the CPU and graphics into a single package is a winner.
Given that laptops are increasingly the most popular sort of PCs, that puts a very different complexion on the whole fusion project.
Intel has duly delivered on its promise to deliver quad-core levels of performance in return for dual-core power consumption.
In fact, this new dual-core mobile CPU is so good, we're struggling to see the need for quad-core laptops at all. It's the biggest step forward in usable laptop performance we've yet seen.
Two things, pricing and branding. In other words, the product is very good indeed, but we have issues with the way Intel is serving it up.
This sort of performance should be a basic human right, as far as we're concerned. But at £250 for this chip alone, any resulting notebook is going to cost proper money.
As for the branding, well, what more can we say? This chip goes by the Core i7 moniker, which makes it the third such entirely unique processor design to do so.
Meanwhile, you can buy a lower clocked but otherwise largely identical version of this very processor under the Core i5 and Core i3 brands.
In other words, the brands Core i3, i5 and i7 have ceased to mean anything. It's potty.
A wide range of laptops based on this and other members of Intel's new range of Core i3, i5 and i7 Mobile chips are already available from the usual suspects including Dell, Toshiba, Sony and the rest.
Countless more will appear in the coming months. If you're in the market for a new portable, be it big, small or anywhere in between, Intel's new mobile processors should be right at the top of your list.