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Power, Efficiency, And Battery Life

AVADirect's W860CU: Mobility Radeon HD 5870 Vs. GeForce GTX 285M
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Given its Radeon HD 5770-based architecture, we are surprised to find the Mobility Radeon HD 5870 with higher idle power than the GeForce GTX 285M. Because it’s part of global wattage measurements, higher GPU idle power also affects the CPU Full Load test reading. The GeForce GTX 285M has higher GPU load wattage, while far higher power draw for the desktop platform shows why these types of parts are not used in notebooks.

Battery Eater Pro runs a small 3D demo continuously. Given the Mobility Radeon HD 5870’s lower load power, we are surprised to see that the unit provides less battery run time. A relatively short battery life from a desktop replacement makes it worth considering the spare battery option if you spend a lot of time away from wall sockets.

The average performance chart above gives us the “work” side of the efficiency equation.

AVADirect’s GeForce GTX 285M build edges out its Mobility Radeon HD 5870 version. The desktop PC’s superior graphics performance softens the fact that it isn't as efficient as the AVADirect notebooks.

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  • 2 Hide
    DjEaZy , May 13, 2010 6:37 AM
    ... do they have AMD CPU's too?
  • 0 Hide
    anamaniac , May 13, 2010 6:42 AM
    How many partners use Clevo laptops and just rebrand them?
  • 1 Hide
    ta152h , May 13, 2010 6:43 AM
    I'm a little confused why you'd choose an i7 920 to compare with a different platform, but maybe it's because I don't know the mobile platform that well.

    But, if it's like the P55, which it seems to be, there's the added uncertainty of the architecture thrown in.

    Particularly with PCI-E being implemented differently, you might be seeing the inferior implementation of the P55 architecture responsible for a small amount of the relatively poor mobile performance. Since this implementation needs to multiplex the memory bus of the processor, you can run into situations where there is contention.

    I doubt it's significant, but I'm curious why you wouldn't want to make a comparison with a more similar desktop platform. Was it because you couldn't get an unlocked Lynnfield to get the clock speeds for the processors the same in Turbo mode?
  • 9 Hide
    Anonymous , May 13, 2010 6:48 AM
    This doesn't make much sense to me... if a 5870M chip = roughly a 5770 desktop chip and a 285M = roughly an 8800gts.. why is it not completely spanking it? we all know 5770>8800.. by a rather large margin! what could be the cause of this?
  • 2 Hide
    anamaniac , May 13, 2010 7:04 AM
    Tom's, you should show your power usage results to AMD and ask for an explanation, on why a lower rated part is using more power.
    Granted, with a 45W CPU and 50W GPU, 30 mins is expected on a 40W battery if fully stressed.
  • -7 Hide
    gti88 , May 13, 2010 7:37 AM
    It's not "mobile gaming" at all.
    So, is there any reason to own such notebuook?
  • 1 Hide
    jkeopka , May 13, 2010 7:41 AM
    I liked this article because I found it so darn relevant... I actually have this same Clevo Laptop, with the 5870 and 8 gigs of RAM.

    The GTX 285M was a $50 premium over the 5870, and I am glad I chose to stick to the 5870. It is kind of strange one would pay more to have less performance. I guess thats what fanboyism are all about?
  • 3 Hide
    jkeopka , May 13, 2010 7:41 AM
    anamaniacHow many partners use Clevo laptops and just rebrand them?

    Lots. Mine is a Sager 8690... which is a rebranded Clevo W860CU...

    I have seen this model at other sites as well.
  • -2 Hide
    falchard , May 13, 2010 7:44 AM
    Looks more like a bottleneck then anything conclusive. The results in nearly all the tests were close, yet 1 of them should have been clearly ahead.
    I think an ASUS JH73-A1 verse this would have been more interesting as its a bit cheaper for better parts.
  • 1 Hide
    Crashman , May 13, 2010 8:42 AM
    TA152HI'm a little confused why you'd choose an i7 920 to compare with a different platform
    Same speeds in Turbo mode, which is used during games, the primary focus being gaming performance.
    TA152HBut, if it's like the P55, which it seems to be, there's the added uncertainty of the architecture thrown in.
    That's true, but neither graphics solution provided the performance needed to highlight the mobile processor's on-die PCIe controller's performance advantage.
    TA152HI'm curious why you wouldn't want to make a comparison with a more similar desktop platform. Was it because you couldn't get an unlocked Lynnfield to get the clock speeds for the processors the same in Turbo mode?
    Exactly. Besides, Tom's Hardware has already seen that clock-for-clock, Lynfield games at least as well as Bloomfield when a single card is used. If nothing else, the comparison favors the mobile solution's lower power consumption.
  • 4 Hide
    Crashman , May 13, 2010 8:44 AM
    demomanisbestThis doesn't make much sense to me... if a 5870M chip = roughly a 5770 desktop chip and a 285M = roughly an 8800gts.. why is it not completely spanking it? we all know 5770>8800.. by a rather large margin! what could be the cause of this?

    Drivers maybe?
  • 0 Hide
    liquidsnake718 , May 13, 2010 8:45 AM
    anamaniacTom's, you should show your power usage results to AMD and ask for an explanation, on why a lower rated part is using more power.Granted, with a 45W CPU and 50W GPU, 30 mins is expected on a 40W battery if fully stressed.


    I also agree with this poster. It would be useful to learn the average battery time these units would work under various loads such as surfing, gaming, movies, and idle. I am also aware of the different settings but you can easily make a benchmark for this. This would be great to compare with the early core i7 laptops like the Eurocom and Cyberpower laptops that lasted only 45minutes to 1hour on average loads.

    Also heat is a factor for many buyers, especially buyers of a core i7 laptop. Sound is not much of a factor anymore with SSD's but one can still read and appreciate a chart for the db of the gpu and cpu fans but this is minor.

    Maybe you can create a core i7 gaming laptop comparison and compare gen1 vs gen 2 core i7 laptops as well which would probably please some serious buyers(not me) in the mobile gaming arena.
  • -2 Hide
    killerclick , May 13, 2010 9:21 AM
    "Gaming notebooks" are for suckers with too much money. Putting up with slower, ridiculously expensive hardware and smaller screens in order to be able to play in school or... where? Where do you "gaming notebook" guys play your games anyway?
  • 1 Hide
    dragonsqrrl , May 13, 2010 9:52 AM
    demomanisbestThis doesn't make much sense to me... if a 5870M chip = roughly a 5770 desktop chip and a 285M = roughly an 8800gts.. why is it not completely spanking it? we all know 5770>8800.. by a rather large margin! what could be the cause of this?

    Actually the HD5770 vs. 8800gts 512 isn't as much of a blow out as you might think. The HD5770 performs roughly on par with the HD4870, and on average these two cards perform just a few percentage points faster then the GTS 250, a card that also uses the g92 GPU and is basically an overclocked 8800gts 512. In fact the only real differences between the GTS 250 and the 8800gts 512 is the manufacturing process/die size and clock speeds, the GTS 250 is 55nm while the 8800gts 512 is 65nm. So in in this way the GTX 285M actually shares more similarities with the GTS 250 then the 8800, although the GTX 285M is severely under-clocked by comparison.

    When you think about it in this way, the fact that a significantly under-clocked GTS 250 is capable of performing similarly to a significantly under-clocked HD5770 really isn't much of a surprise. However the Mobility HD5870 does have one considerable advantage over GTX 285M, the inclusion of DX11 support. But considering the generational gap between these two cards I don't think this is a huge disadvantage for Nvidia.

    The bigger issue in my opinion is the performance of the Mobility HD5870 and its real world power consumption in comparison to its published TDP. ATI's new flagship mobile GPU is able to perform marginally better then the GTX 285M. This is against a mobile card that's well over a year old and soon to be replaced by the GTX 480M. I understand the rational behind ATI and Nvidia using their midrange GPU's in their high end mobile offerings (POWER CONSUMPTION), but I honestly think ATI should have bumped up the clock speed a bit more for the sake of next gen performance competitiveness. And I find it strange that two cards with significantly different TDP's would consume similar amounts of power... there's definitely something strange going on in that regard, especially considering the supposed 50W TDP of the Mobility HD5870.
  • 2 Hide
    masterjaw , May 13, 2010 9:57 AM
    ^ In other places aside from home, maybe. Like LAN parties, perhaps.

    Gaming notebooks are already gaining a quite niche of market. But still, as observed before, the performance gap is enormous compared to desktop PCs.

    I would be interesting if you compare these to ASUS gaming notebooks as well.
  • 3 Hide
    sakanagai , May 13, 2010 10:14 AM
    The fourth page has the tables in the wrong places. The Nvidia analysis follows the ATI chart, while the analysis on the ATI parts follows the Nvidia chart.
  • 4 Hide
    drowned , May 13, 2010 10:15 AM
    Max PC mag tested the 285M SLI version of this and found it gave about 1:10 battery life when playing a dvd with all power saving stuff enabled at 50% brightness. Honestly though, this isn't a notebook...it's a desktop that folds in half.
  • 1 Hide
    dragonsqrrl , May 13, 2010 10:32 AM
    Nice article. I wouldn't have a problem with using midrange desktop GPU's in high-end mobile cards if it weren't for these ridiculous prices. $400... are you kidding me? I understand that given the power consumption of current gen high-end desktop cards, there's simply no way ATI or Nvidia could transfer a Cypress or gf100 into a notebook and deliver reasonable performance at a reasonable TDP. It's more efficient at the moment to use mid-range GPU's instead. So I don't really think this trend was born out of an attempt to purposely deceive (ignorant?) customers, so much as it was born out of necessity.

    The pricing however is a completely different story, and I think a mid-range GPU should be priced like a mid-range GPU, no matter how it's re-branded. Charging the same price as a desktop HD5870 for a GPU with half the transistor count and less then half the performance is the true deception.
  • 3 Hide
    juliom , May 13, 2010 11:17 AM
    dragonsqrrlActually the HD5770 vs. 8800gts 512 isn't as much of a blow out as you might think. The HD5770 performs roughly on par with the HD4870, and on average these two cards perform just a few percentage points faster then the GTS 250, a card that also uses the g92 GPU and is basically an overclocked 8800gts 512. In fact the only real differences between the GTS 250 and the 8800gts 512 is the manufacturing process/die size and clock speeds, the GTS 250 is 55nm while the 8800gts 512 is 65nm. So in in this way the GTX 285M actually shares more similarities with the GTS 250 then the 8800, although the GTX 285M is severely under-clocked by comparison. When you think about it in this way, the fact that a significantly under-clocked GTS 250 is capable of performing similarly to a significantly under-clocked HD5770 really isn't much of a surprise. However the Mobility HD5870 does have one considerable advantage over GTX 285M, the inclusion of DX11 support. But considering the generational gap between these two cards I don't think this is a huge disadvantage for Nvidia.The bigger issue in my opinion is the performance of the Mobility HD5870 and its real world power consumption in comparison to its published TDP. ATI's new flagship mobile GPU is able to perform marginally better then the GTX 285M. This is against a mobile card that's well over a year old and soon to be replaced by the GTX 480M. I understand the rational behind ATI and Nvidia using their midrange GPU's in their high end mobile offerings (POWER CONSUMPTION), but I honestly think ATI should have bumped up the clock speed a bit more for the sake of next gen performance competitiveness. And I find it strange that two cards with significantly different TDP's would consume similar amounts of power... there's definitely something strange going on in that regard, especially considering the supposed 50W TDP of the Mobility HD5870.


    You're mistaken. The 4850 performs roughly on par with the GTS 250, not the 4870 which is way faster. The 4870 performs as a GTX 260 with 216 cores and the 4890 like a GTX 275.
  • 0 Hide
    Anonymous , May 13, 2010 1:21 PM
    It's not about whether AMD followed Nvidia's naming scheme, it's about taking the beating on sales. So AMD is supposed to keep their honest naming approach for the sake of us few enthusiasts, while Nvidia makes the bank on non-enthusiasts who don't check the facts and don't read the reviews? I fully support AMD in mimicking Nvidia's practices in this case, they were left no choice.
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