Power

Closely related to battery life is the topic of system power draw. After all, a system that requires more power to run will typically provide less battery life. We used a Kill-A-Watt device with the batteries removed in order to record system power requirements. We also tested with minimum and maximum display brightness to show how that particular setting affects power draw, except on the maximum load where we used the brightest display setting. Please note that these are most definitely not equivalent configurations: the ASUS has a larger LCD, faster GPU, and a larger 7200 RPM hard drive, all of which should increase power use. Here are the results.

System Power Draw (Watts)
Boo! Scared you! Idle 100% CPU Maximum
ASUS A8JS 26-32 47-52 71
MSI TL-50 2x512MB 17-21 43-48 58
MSI TL-50 2x1024MB 17-22 45-50 61
MSI TL-60 2x1024MB 19-24 50-56 66

The MSI configuration with the slower TL-50 processor clearly consumes the least power. However, what's interesting is when we get to the "equivalent" configurations. The ASUS laptop still has a faster graphics processor, but what's particularly interesting is that it's the idle power consumption that really seems to affect battery life of the ASUS laptop the most. When the CPU is under full load, the ASUS system actually uses less power than the TL-60 MSI configuration. Adding graphics work to the CPU load results in the ASUS using slightly more power, but considering the higher performance it offers the extra 5W is a reasonable sacrifice. The problem comes in idle power draw, where the ASUS laptop consumes 7-8W more power than the MSI TL-60.

This leads us to an interesting conclusion in regards to battery life and power requirements. First, at maximum load the GeForce Go 7700 really doesn't apprear too bad, all told. At idle, the GPU seems to hurt the ASUS in power draw, although it could also be that the Core 2 Duo chip isn't dropping to as low a power state relative to the Turion X2. The likely explanation has to do with the old topic of AMD's integrated memory controller, along with CPU clock speeds. Both the Core 2 Duo and Turion X2 regulate processor speed by changing the CPU multiplier, but the final result is different.

First, the Turion X2 has a lower minimum multiplier of 4X with a HyperTransport bus speed of 200 MHz, resulting in a CPU speed of 800 MHz. That might seem like a relatively slow processor these days, but if your system is just sitting idle you don't need a lot of unused clock cycles. In contrast, Core 2 Duo has a minimum multiplier of 6X with a bus speed of 166 MHz, resulting in a minimum clock speed of 1000 MHz. Right there, Core 2 Duo is running 25% faster (proportionately) in its lowest sleep state.

Going back to the integrated memory controller, AMD also reduces your memory performance along with the slower CPU speed in order to further conserve power. AMD bases your memory speed off of the CPU speed, and in the case of the TL-60 using DDR2-533, at maximum CPU speed the memory is running at CPU/8 or DDR2-500. When the CPU goes into sleep state, the memory divider is also modified. In the sleep state, the memory runs at CPU/5 or DDR2-320. Memory and CPU voltages are also reduced, so the net result is that AMD is able to use less power when the system is in an idle state.

Does that make the Core 2 Duo worse at power saving than Turion X2? Without equivalent setups (i.e. both using IGP or both using discrete GPUs), we can't say for certain. We can say that an ASUS W5F with a T2300 chip (1.67GHz 2MB cache) that we had at one point bottomed out at 19W in idle mode, so Core Duo and Turion X2 appear close in low power states, with Turion X2 perhaps holding a slight 1-2W advantage. Our testing of Core Duo vs. Core 2 Duo showed the CPUs to be nearly equal in power draw, so it appears AMD is equal or slightly better than Intel at minimum power draw. At maximum power draw by the CPU, Turion X2 is definitely using more power than Core 2 Duo, as even with higher performance/power components the ASUS A8JS still uses less power than the MSI TL-60 at 100% CPU load.

Temperatures

So with the information on power requirements and performance, some of you are probably wondering how hot these systems get. Are they truly "laptops", or would they be more at home on the top of a desk or table instead? We checked temperatures over the surfaces of both systems in their maximum configurations at full load. The systems were placed on a flat, hard table surface with an ambient temperature of 23°C.

System Temperatures (Celcius)
Trick or treat? Palm Rest Keyboard Bottom Exhaust
ASUS A8JS 25-32 31-36 25-39 46
MSI TL-60 2x1024MB 27-31 31-38 29-41 48

There are several factors at play here. First, from the power requirements we know that the ASUS laptop is only consuming slightly more power. This is counteracted by the fact that it has a larger surface area, resulting in overall lower temperatures. We didn't tear apart the ASUS system in this article, but the cooling configuration is also slightly different, and there are more vents on the bottom of the ASUS A8JS. Both systems remained quiet during use even under maximum load (right around 30 dB, which is the limit of our SPL meter), but the ASUS was slightly (< 2 dB) louder during gaming sessions where the GPU and CPU are both active. More fan noise means more cooling power, which can also account for the lower temperatures on the ASUS system.

The surfaces of both laptops range from just slightly higher than room temperature up to moderately warm. Neither gets extremely hot, and most people would be okay with placing these systems on your legs, even with direct skin contact (don't mind the sweat). The only real problem we have with using either system on your lap is that this would tend to block the system fan intake, which could lead to higher temperatures and possibly even stability problems. We did use both systems in less ideal situations where the fan intake was at least partially obstructed, however, and didn't encounter and issues.

Battery Life A Quick Look at Gaming/Graphics Performance
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  • JarredWalton - Monday, October 16, 2006 - link

    First, the "closed system" as such is not something we would recommend. Dual core with only 512MB of RAM? I already covered that. Second, the system *is* available as a barebones (MSI MS-1058), as I mentioned in the review. Memory compatibility aside, this isn't a great laptop. It's okay.

    The memory issues are something worth mentioning, even if we got them worked out. Even if everything had worked without issue, the laptop would have still only been okay - there are quite a few competing notebooks in the same price range, and this one fails to stand out from the crowd in any meaningful way.
    Reply
  • Furen - Monday, October 16, 2006 - link

    Sounds like you had huge memory compatibility problems, though. Personally, I always buy Crucial because when I used to buy other RAM (Kingston, etc), more often than not, I had some sort of memory compatibility problems (probably because I mixed brands but I've never had ANY problems at all with Crucial stuff). Reply
  • DrMrLordX - Monday, October 16, 2006 - link

    I know the Core Duo is now an old product that is being replaced by the Core 2 Duo in the mobile sector, but it would have been nice to see the Turion X2 benchmarked against a Core Duo laptop as well. Surely a similarly-configured Core Duo machine exists out there somewhere. Reply
  • IntelUser2000 - Monday, October 16, 2006 - link

    One thing is the Core 2 Duo laptop has 7200RPM HDD while the Turion X2 has 5400RPM. It shouldn't impact is greatly but it'll make a difference. Reply
  • IntelUser2000 - Monday, October 16, 2006 - link

    quote:

    This leads us to an interesting conclusion in regards to battery life and power requirements. As best we can tell, it appears that the Core 2 Duo processor actually requires less power than the equivalent Turion X2 processor when both are placed under full load.


    Uhh. No. Clearly no. Explanation?? Turion X2 system uses integrated graphics, while Core 2 Duo system uses a powerful video card. Do you guys really think idle power of video card+chipset is equal to chipset alone??
    Reply
  • IntelUser2000 - Monday, October 16, 2006 - link

    http://www.computerbase.de/artikel/hardware/grafik...">http://www.computerbase.de/artikel/hard...hnitt_le...

    Integrated graphics power is clearly lower than even super low-end discrete. Now on this AT review we are talking about a mid-range part.

    Sorry for triple post, but I must get my point across.

    Two laptops, each possessed by one of my friends, both a Dell:
    Pentium M 765 2.0GHz/533MHz FSB
    1GB DDR2-533
    120GB 5400RPM HDD
    Geforce Go 7800GTX 128MB
    15.4 inch wide-screen
    70WHr battery
    2.5 hour battery life with internet surfing, usage

    2. Pentium M 1.6GHz/400MHz FSB/Dothan
    512MB DDR2-533
    Intel GMA900
    60GB 4200RPM HDD
    14 inch screen
    45WHr battery
    3.5 hour battery life with internet surfing, light usage

    Is there a reason some high-end laptops are featured with integrated/discrete graphics card option?? You can turn one off?? Cause video cards in laptops suck huge amounts of power.
    Reply
  • JarredWalton - Monday, October 16, 2006 - link

    There are multiple issues involved with testing comparable laptops. Short of going out and purchasing a laptop, it's very difficult to pull off. At this point, there's not much reason to get a Core Duo notebook instead of a Core 2 Duo notebook, other than price. So we're doing our best to compare laptops that are similar, and we wanted to get this review out the door before it got any older. Obviously, we're still not recommending the MSI S271 over other laptops.

    In regards to Inteluser2000, he makes several comments. I have now reworded the page on power consumption to clarify a few points. However, not all of his points are entirely valid either. For example:
    quote:

    No. Clearly no. Explanation?? Turion X2 system uses integrated graphics, while Core 2 Duo system uses a powerful video card. Do you guys really think idle power of video card+chipset is equal to chipset alone??


    I don't think he was reading clearly, because I had just explained that at maximum CPU load MSI Turion X2 is consuming MORE power than ASUS Core 2 Duo. In other words, even with integrated graphics versus discrete graphics and with all of the other variables involved (7200 RPM hard drive versus 5400 RPM Drive, 14 inch LCD versus 12.1 inch LCD, etc.), without putting a load on the GPU one would expect the ASUS system to draw more power than the MSI system, and it doesn't. At idle, all of the variables can explain why the ASUS consumes more power, but when I put 100% load on just the CPU Turion X2 clearly requires more power.

    I have no idea what he is trying to say with his comment about Dell laptops. Comparing a high-end system with a GeForce Go 7800 GTX to one that uses IGP is far worse than comparing something that uses GeForce Go 7700 to IGP. Different battery sizes, different display sizes, different processors, different hard drives, memory, etc. -- of course they're going to have different results. However, in this case are not drawing any final conclusions about idle power, other than to point out some interesting trends. What I am concluding is that if we were able to isolate just the CPU power use, a Turion X2 TL-60 at 100% load would require a lot more power than a Core 2 Duo T7200 at 100% load.

    The ASUS system is there more as a frame of reference, particularly on the power requirements page. I really can't say for certain whether Turion X2 uses more power or less power at idle, but I am positive that it requires more power when it's placed under 100% load. Hope that explains things.
    Reply
  • IntelUser2000 - Monday, October 16, 2006 - link

    quote:

    I don't think he was reading clearly, because I had just explained that at maximum CPU load MSI Turion X2 is consuming MORE power than ASUS Core 2 Duo. In other words, even with integrated graphics versus discrete graphics and with all of the other variables involved (7200 RPM hard drive versus 5400 RPM Drive, 14 inch LCD versus 12.1 inch LCD, etc.), without putting a load on the GPU one would expect the ASUS system to draw more power than the MSI system, and it doesn't.


    Nonono. I don't care about the load power, I care about your conclusions regarding idle. Even if you don't put load on the GPU, it consumes power. In laptop standards, lots of power. Its not a coincidence some laptop manufacturers put dual video card solutions(integrated/discrete), because they realize discrete cards affect battery life in idle, not just load. What I don't like is the explanation that its the CPU and chipset that contributes to idle power consumption and less battery life at DVD playback, Mobilemark, etc.

    Check this out: http://www.trustedreviews.com/article.aspx?page=50...">http://www.trustedreviews.com/article.aspx?page=50...
    (Dual GPU machine)

    DVD playback
    IGP: 164 minutes
    Nvidia Geforce Go 6600: 112 minutes

    MobileMark 2005 general battery life test
    IGP:128 minutes
    Geforce Go 6600: 92 minutes

    30-40% battery life difference. Looks like video card is quite a big drain on battery life. I bet significant battery life difference between my friend's two system lies in the video card.

    This is really a laptop review rather than a CPU review. Of course, due to laptops peculiarity of outperforming one with what looks like similar specifications, the idea of a CPU comparison on a laptop is far-fetched.
    Reply
  • JarredWalton - Monday, October 16, 2006 - link

    I did reword the rest of the page in regards to power use. I have used an ASUS W5F and found that it used about the same amount of power as the S271 (at idle). It was slightly more, so the remaining conclusions (i.e. Turion X2 in low power mode uses a bit less power) seem to be consistent. Tough to say 100% without nearly identical laptops - and you still have chipset and mobo components that can have an impact. Reply
  • IntelUser2000 - Monday, October 16, 2006 - link

    quote:

    I did reword the rest of the page in regards to power use. I have used an ASUS W5F and found that it used about the same amount of power as the S271 (at idle). It was slightly more, so the remaining conclusions (i.e. Turion X2 in low power mode uses a bit less power) seem to be consistent. Tough to say 100% without nearly identical laptops - and you still have chipset and mobo components that can have an impact.


    You can find otherwise similar looking laptops that have different power consumption. How did you test out the W5F?? Just dropped in a Core 2 Duo in replacement of Core Duo?

    Otherwise nice test.
    Reply

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