Mobile Core i7 920XM, Clarksfield: Nehalem on-the-go
by Jarred Walton on September 23, 2009 10:00 AM EST- Posted in
- Laptops
Initial Thoughts
It's good to finally see an official Nehalem CPU for the mobile sector. Power gate transistors have the potential to seriously improve battery life, and we can't wait to see that sort of technology begin making its way into GPUs and chipsets as well as processors. In terms of performance, things are a little bit of a mixed bag.
Certainly the i7-920XM is a fast processor; the problem is that it's also a relatively power hungry processor, and without a larger battery users of the W87CU can expect roughly the same one hour of battery life you get with other desktop replacements. As long as you understand you're getting a desktop replacement, however, the W87CU should work fine. The real problem isn't competition from the mobile sector per se, but rather the notebooks that use desktop CPUs - specifically desktop i7 CPUs. If you don't care that much about battery life, wouldn't you rather have a desktop replacement with a $1000 Core i7-975 instead of a $1000 Core i7 920? If you're wealthy it probably doesn't matter much, but the rest of us will need to think very carefully about how much we want a faster laptop before taking the Clarksfield plunge. For CPU intensive tasks, the AVADirect D900F system can easily outperform a W87CU for about the same price (though it does weigh more).
If there's anything Clarksfield shows us, it's that we really want Arrandale - sooner rather than later. Quad-core processors simply aren't a major need for the vast majority of laptop users, and the higher prices and higher maximum TDP make them less desirable. Arrandale should do a great job at addressing both of those shortcomings, and the same goes for Clarkdale on the desktop. Lower power dual-core processors with Hyper-Threading will still have the ability to run four simultaneous threads, and they should also be able to run at higher clock speeds most of the time.
We will have additional benchmark results and discussion of the pros and cons of the various laptops tested in this article in the near future. Considering pricing is similar on all three models, however, users will need to decide what they want most. Mobile gamers will definitely want something with dual graphics capability, and content creators will prefer something similar to the D900F. The question is, who fits in the middle? Clarksfield could go either way, offering a reasonable blend of CPU performance and power requirements. It's almost inevitable that we will see Clarksfield laptops in the future that also offer dual GPUs, at which point we might be onto the next Intel "Tock". However you look at it, high-end laptop users just got some new choices, and freedom of choice is always a good thing.
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JarredWalton - Wednesday, September 23, 2009 - link
Regarding the "max brightness", that was actually incorrect. I used new values for the laptops with the LCDs always at 100 nits. It's still not a perfect comparison, since one LCD at 100 nits might use 3W and another could use 8W depending on size and backlight technology, but it's closer than using the max brightness (as your comments indicate).FWIW, Core 2 Quad QX9300 and the i7-920XM appear similar in max power draw but with the i7 part having far better idle power. A C2Q with two 10W CPUs would end up running at 1.6GHz tops and use ~20W TDP, but idle power still won't be as good as the 920XM because of Power Gate. What would be really interesting would be Power Gate tech moved into Core 2 CPUs, but that ain't gonna happen anytime soon I suspect. :)
gstrickler - Thursday, September 24, 2009 - link
Can the QX9300 on the Eurocom system be clocked down to 2.0GHz? Can you disable Turbo and HT on the Core i7-920XM on the Clevo W87CU system? If so, you could compare a C2Q @ 2.0GHz vs a 920XM @ 2.0GHz (with and without HT). Run CPU (not GPU) intensive tasks and see how they perform and how much load power they each use. That should give a good indication of the relative instructions per clock of the two architectures as well as the performance/watt.There is no need to repeat any of the gaming tests, just a couple single threaded and multithreaded CPU intensive tests and idle and full CPU load power usage. It might let us put to rest the lingering questions of whether C2D or Core i7 is a better core architecture for mobile systems.
Granted, there are still other system differences that we can't eliminate, but as long as SLI is not enabled on the Eurocom system, we can get them to be fairly close.
gstrickler - Wednesday, September 23, 2009 - link
Agreed. Aside from better power management (power gating and turbo mode), I'm not yet convinced that the Core i7 is more power efficient than C2. I don't expect to ever see it, but a C2Q with the power management of the i7 might make an excellent laptop CPU.As for the "Max brightness" comment, I was addressing the other poster's reply about tests of the Dell Studio 16, don't know the 100nit level was used there, but as noted, power can still vary significantly.
JarredWalton - Wednesday, September 23, 2009 - link
Arrandale is what we want, really: dual-core with HyperThreading. That should cut maximum CPU power use down substantially, and there will be 25W and 35W parts (and likely 17W as well). Restricting Turbo modes to lower clocks will also help. Right now, Clarksfield is max performance within a much greater thermal envelope than most laptops allow.Wolfpup - Thursday, October 15, 2009 - link
*I* want a quad core laptop! No question dual core is kind of anemic anymore. I mean it's been silly to go dual core on the desktop for YEARS, yet we're still stuck mostly with dual core on notebooks :-/I'm really more interested in how those 1.6 and 1.73Ghz parts do versus faster clocked Core 2 duos and quads. The clock speed obviously is kind of frighteningly low, so I sort of need to see benchmarks that 1.6 or 1.73 actually gives you a competent system (I'm sure it does, but...)
And yeah, I game on my 2.4Ghz Penryn dual core with mobile Geforce 9650GT. I'd like better, but a desktop isn't an option for me anymore, so I'll just upgrade my notebook as needed :)
gstrickler - Wednesday, September 23, 2009 - link
While Arrandale is promising, I would be similarly interested in a 25W C2Q. Since they can make 10W and 17W C2D, they should certainly be able to make 25W and 35W C2Q. Arrandale should be faster when running 1 or 2 threads, but a 1.6GHz C2Q @ 20W TDP (2 x SU9600) should perform as well or better when running all 4 cores. As a bonus, the C2Q could work with the Nvidia 9400M chipset, for very good IGP performance, add an optional discreet GPU for those who want something faster. Until Intel demonstrates that they can actually deliver a good IGP, Arrandale doesn't sound all that wonderful. Just a thought.gstrickler - Wednesday, September 23, 2009 - link
Let me clarify a bit. I would be far more interested in the Core i# CPUs if it didn't have an Intel GPU built in and if I had an option of a good non Intel chipset. Since Intel and Nvidia seem to be in a pissing contest over the licensing that would allow Nvidia to build an i# compatible chipset, the future of a low power CPU, chipset, and GPU (that doesn't suck) looks questionable on Arrandale.For those of us who don't need a discreet GPU, but want decent graphics performance AND excellent battery life, an all Intel solution does not look promising. At best, it looks like a 25W Arrandale with an Intel chipset and a discreet low power ATI or Nvidia GPU.
While HT on the Core i# CPUs is better than HT on P4, it's still nowhere near the benefit of doubling the real cores. I would rather have a non HT (e.g. Core i5) based quad core than Arrandale.
yacoub - Wednesday, September 23, 2009 - link
55% market share is laptops but they don't mention if those people also own a desktop - or more importantly, build their own desktop.When you consider that more and more of the people who want a desktop are enthusiasts who build their own, and those numbers aren't going to be counted in desktop sales which only considers the pre-built big-box manufacturers like Dell, etc, you realize that chart means little.
So in reality the chart is a great marketing tool: It's "true" in one sense, but it doesn't tell the whole story.
jordanclock - Thursday, September 24, 2009 - link
Pre-built machines from Dell, HP, Apple, etc. account for the vast majority of systems sold. Custom built computers are a niche. I suspect custom build computers would be lost in the margin of error.pervisanathema - Wednesday, September 23, 2009 - link
What means little is your phantom statistic "when you consider that more and more of the people who want a blah blah blah."That' your opinion. You have no evidence to back that up. My opinion is that you are very wrong and that most people just buy the cheapest prebuilt rig they can find.