Power Consumption

The beauty of a console is that the specs never change, so while AMD, Intel and NVIDIA have to try to add new features or increase clock speeds with each die shrink, Microsoft gets to sit back and reap the benefits of cooler running hardware that's cheaper to manufacture. The move from Xenon to Falcon resulted in a pretty significant reduction in power consumption; under full load a Falcon Xbox 360 drew less power than a Xenon unit at idle.

The Falcon to Jasper transition isn't quite as dramatic unfortunately. I ran five power tests, I looked at power consumption at the NXE dashboard at idle, power consumption at the main menu of Rockband 2, Halo 3 and Gears of War 2, and finally if you don't own any of these games but want a comparison point I looked at power consumption of the Xbox 360 while running the BioShock demo (at the very start of the demo when you find yourself in the water surrounded by fire). Power consumption during actual gameplay doesn't go up much, if at all, compared to the start screens for these games - the main menu screens are all rendered in 3D and are apparently just as stressful as the games themselves, plus they're a very consistent way of measuring power consumption.

I used a Watts-Up meter which the Xbox 360 plugged into, so what we're looking at here is total system power consumption.

Xbox 360 Revision System Off Idle Halo 3 Rockband 2 Gears of War 2 BioShock Demo
Xenon 2.3W 155.7W 177.8W 167.7W 177.1W 172W
Falcon 2.8W 101.4W 121.2W 112.8W 121.5W 115.5W
Jasper 2.0W 93.7W 105.9W 101.0W 105.9W 98.1W

 

Overall you're looking at a 12% reduction in total system power under load and under 8% at idle, definitely not the ~30 - 35% drop we saw with the Xenon to Falcon transition, but not insignificant either. Remember that the smaller your transistors get, the more leakage current becomes a problem; while your transistors use less power, they also tend to use more power when they are in a logical off state than they should. There have also been a number of advancements in architecting for low power designs over the past couple of years that Microsoft hasn't taken advantage of as they would require a redesign of the 360's CPU/GPU. Microsoft is in full blown cost savings mode with the Xbox 360, the only things that will be done to that console before it dies are things to improve the Xbox division's bottom line.

Final Words

There you have it. Jasper is out and now we play the waiting game to see if the dreaded RRoD is finally solved with the latest batch of hardware changes. Even if it's not, if you are buying an Xbox 360 today you might as well opt for the cooler running, newly redesigned Jasper model rather than the year-old Falcon. Why pay the same amount for old hardware, it's just not the AnandTech way.

And once again, to those of you with Jaspers: congrats, after 3 years you may have just bought an Xbox 360 that won't die.

Jasper Dissection
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  • kilkennycat - Wednesday, December 10, 2008 - link

    Yep, and for the latest classic example, consider the PC port of GTA4. This port hold the all-time (so far) rotten-banana-prize for the worst console to PC port of a major video-game. Besides the DRM and gross game-play/graphics bugs, the game REQUIRES at least 3 CPU-cores for optimum performance. Code obviously ported over from the 3-core Xbox360 version, with zero optimization for a fewer number of far more capable PC CPU cores. The cartoon-type graphics puts little stress on the GPU. Hopefully, Anandtech in one of the occasional PC game-related articles will lacerate Rockstar and Take Two for this lazily-awful port to the PC. Reply
  • seriouscat - Wednesday, December 10, 2008 - link

    Comon AT! Wheres the temperature benchmarks? This was the single most interesting test I was looking foward to after all these months and what do I read? Nothing! Reply
  • Pirks - Wednesday, December 10, 2008 - link

    Otherwise he wouldn't write "I'm actually a bit surprised that we haven't seen more focus on delivering incredible visuals on PC games given the existing performance gap" because the answer to that has been printed in media many times, and here it is posted on DailyTech this morning: http://www.dailytech.com/article.aspx?newsid=13648">http://www.dailytech.com/article.aspx?newsid=13648

    See Anand, it's really easy to make you stop feeling surprised. You won't ever now, will ya? Just remember this P-word, always remember it.
    Reply
  • Gunbuster - Wednesday, December 10, 2008 - link

    "Most lead-free replacements for conventional Sn60/Pb40 and Sn63/Pb37 solder have melting points from 5–20 °C higher"

    You need to back up your facts in this one boys.
    Reply
  • Staples - Wednesday, December 10, 2008 - link

    I have yet to see someone hook up a Jasper to a current meter to test out how much power the darn thing draws.

    I hope this does cure the RROD because my launch system (Xenon) and the Falcon I bought a year ago both have gone bad. The Falcon used much less power but if the GPU was the real cause of the RROD like many speculate, then hopefully this die shrink takes care of it.

    And for all of those who do not know which version you have, do what I do. I have never once looked into the console with a flashlight. I have a kill a watt meter and by comparing anand's numbers to that of your own will narrow down the generation of Xbox you have.
    Reply
  • ss284 - Wednesday, December 10, 2008 - link

    Power(W) = current(A) * voltage(V).

    I'm assuming you can do the math. The killawatt is in essence a volt/current meter.
    Reply
  • sprockkets - Wednesday, December 10, 2008 - link

    Close. Watts is energy. Watts over time is power, or kWh. Reply
  • ahmshaegar - Wednesday, December 10, 2008 - link

    Wow. Can't believe I just saw someone post that.

    The watt is definitely a unit of power. Power is the rate at which you use energy. 1 W = 1 J/s. So the kWh is actually a unit of energy, since you multiply the watt with the hour (a unit of time), which is very odd* if you think about it (1 W = 1 J/s, so 1 kWh is 1000 Wh, or 1000 (J/s)h.

    Because 1 hour contains 3600 seconds, 1 kWh is 1000 joules per second multiplied by 1 hour multiplied by 3600 seconds per hour (this last term converts the 1 hour to seconds, so I can cancel out the seconds.)

    You then get 1 kWh = 3600000 J, proving that the kWh is indeed a unit of energy.

    *It's one of those odd units if you just think about it, but very useful for the utilities.
    Reply
  • adhoc - Wednesday, December 10, 2008 - link

    I don't understand the comment about lead-free solder melting at high temperatures...

    Lead-free solder actually has a HIGHER melting point than leaded solder. Instead of worrying about solder melting at "high temperatures" from chip heat dissipation, I'd be more worried about PCB and component reliabilities due to the initial soldering process. PCB laminates that aren't suited for lead-free/RoHS elevated temperatures can warp and/or delaminate, creating immediate or possibly latent failures.

    Aside from the PCB materials, components need to be characterized for the higher temperatures during the reflow/wave processes. Ceramic capacitors come to mind as a specific issue; the ceramic can crack under high temperatures (especially temperature gradients during hand-soldering), which can eventually create an open circuit, or worse even a short between power planes.

    In the end, I'm just dubious of the explanation of lead-free solder as the failure mode. On the ohter hand, it may very well be related to the required higher temperatures during assembly (and thus bad PCBs and/or component failures).
    Reply
  • The0ne - Wednesday, December 10, 2008 - link

    Some designers don't account for the higher temperatures when they design PCBs. Actually there's quite alot of them around. That and mixing leaded and lead free parts where SMT has a much harder time processing them. In such case, they end up separating the process to lead, lead-free and sometimes even hand solder because of the particular design. Then you have designs that doesn't take into consideration of the distances between components or more specifically between vias. With very fine pitches this can become a nightmare for SMT. Reply

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