Power Consumption and Thermal Profile

The power consumption details and case temperatures at full load were recorded in our earlier piece covering the build of the HTPC. However, we have made some updates to the system with the addition of an extra RAM stick as well as an additional SSD  This time around, we decided to run a stress test with Prime 95 and Furmark for 24 hours. As can be seen below, CoreTemp reports that the core temperatures went as high as 86 C before settling down to around 80 C. The TDP rating of the Core i3-3225 is 55W, and CoreTemp reported between 53.8 W and 54.6 W throughout.

We removed the GPU loading and let Prime 95 alone run for some time. With almost no load on the GPU, the power consumed by the processor jumped down to around 40 W. This thermal budget allocation is pretty interesting, with less than 30% allocated to the GPU and the rest to the CPU. The i3-3225 doesn't have a Turbo mode, and hence, it is unable to take advantage of the headroom offered by the idle GPU.

Average power consumption numbers for various scenarios are presented in the table below. Unless explicity specified, the specified scenario was tested using Windows 8 Pro x64.

Passive Ivy Bridge HTPC (Core i3-3225 / Asus P8Z77-I Deluxe) Power Consumption
   
Windows 7 - Idle (Display off) 27.71 W
Windows 8 - Idle (Display off) 24.86 W
Windows 7 - Idle (Display on) 28.02 W
Windows 8 - Idle (Display on) 26.66 W
Sleep 2.00 W
   
Prime95 v25.9 + Furmark (Full loading of both CPU and GPU) 88.75 W
[Updated: New!] Prime95 v27.7 + Furmark 1.10.3 (Full loading of both CPU and GPU) 89.77 W
Prime95 v25.9 (Full loading of CPU only) 58.25 W
[Updated: New!] Prime95 v27.7 (Full loading of CPU only) 62.56 W
   
1080p24 H.264 Blu-ray Playback from ODD - CyberLink PowerDVD 12 38.15 W
1080p24 VC-1 Blu-ray Playback from ODD - CyberLink PowerDVD 12 37.64 W
1080i60 VC-1 Blu-ray Playback from ODD - CyberLink PowerDVD 12 39.73 W
1080p24 VC-1 Blu-ray ISO Streaming from NAS - CyberLink PowerDVD 12 34.78 W
1080p24 H.264 MVC Blu-ray ISO Streaming from NAS - CyberLink PowerDVD 12 37.86 W
   

In our initial piece, we had noted the case and heat sink temperatures in the Fahrenheit scale. Since the configuration has changed (and the system consumes more power now), we have refreshed the case / heat sink temperature figures below. We have also shifted to the Celsius scale, as requested in some of the reader comments.

Chassis Temperature in C (Top and Faceplate) after 24 Hours of Full CPU / GPU Loading

Chassis Temperature in C (Side Bolted to the Heat Sink) after 24 Hours of Full CPU / GPU Loading

Heat Sink Assembly Temperature in C after 24 Hours of Full CPU / GPU Loading

Software Interface: XBMC and JRiver Media Center 18 Concluding Remarks
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  • Hardcore69 - Sunday, January 20, 2013 - link

    A lot of that GPU accelerated DirectX 11.1 stuff is used way more in the Modern UI than the deskto. And where were the power figures for the desktop version of the apps?
  • ganeshts - Sunday, January 20, 2013 - link

    Which apps are you talking about in particular?

    The Netflix app is the only 'Metro-specific' app that we installed. For comparison, we have power figures for Silverlight and Windows 8 too (if that is what you mean by desktop version of the Netflix app).

    Everything else was the desktop version.
  • mavere - Sunday, January 20, 2013 - link

    Is it possible to analyze where the Windows 8 power savings are coming from? In a couple tests, the benefits were equal to the entire TDP of some systems, and you'd think Microsoft would have advertised that aspect of Win8 more.

    I think I speak for most enthusiasts here when I say that the why and how is often more interesting than the what. :D
  • ganeshts - Tuesday, January 22, 2013 - link

    I think a lot of that has to do with avoiding CPU loading (Silverlight), fully functional GPU accelerated decoding (again, not through Slverlight) and possibly DRM is handled through specialized CPU instructions instead of as a Silverlight component.

    The power differences seem to be non-existent in older systems as per other commenters, but, on modern CPUs / GPUs, it is very evident. So, I suspect a lot has to do with the updates made in the CPUs and GPUs in the last couple of years
  • Midgetsaw - Sunday, January 20, 2013 - link

    This all very well and good but for me a htpc isn't any good without a tv tuner and windows 8 doesnt actually have media center. you have to contact ms to acquire it which is bs, all you have built is a glorified yt player, which you could have probably done with linux.
  • lotharamious - Sunday, January 20, 2013 - link

    Do you have Windows 8 Pro? I'd bet you do.

    Free upgrade from Windows 8 Pro to Windows 8 Pro with Media Center until January 31.

    Go here:
    http://windows.microsoft.com/en-US/windows-8/featu...

    Give them a valid email address and enter the key they give you. Done. Windows 8 with Media Center.

    So difficult to "contact ms", my ass. You just want an excuse to hate. I understand, many are like you.
  • Cygni - Monday, January 21, 2013 - link

    Ah yes, finally I can pay to upgrade my OS to a less usable HTPC version, then either jump through hoops (if its the next week and a half )or PAY EXTRA to restore completely un-upgraded functionality that came free with the version I upgraded from.

    Oh thank you Microsoft, you're truly a gleaming light.
  • euler007 - Monday, January 21, 2013 - link

    I guess free isn't good enough for you. Should they e-mail you a check to earn your anonumous forum support?
  • Golgatha - Monday, January 21, 2013 - link

    My time spent "upgrading" isn't free. Nor do I wish to experiment with Windows 8 further after already being maddened by it's ridiculous (for the desktop anyway) UI. I did try it for a few days and then I imaged back to my Win7 install. I like it better and all my programs work with it without issue.
  • lexluthermiester - Monday, January 21, 2013 - link

    There are a great many of us who feel your pain. I gave The Consumer Preview a shot and I kinda warmed up to it. The Release Preview ruined that warmth. And and fairness, I gave the retail release a solid month before washing my hands of it. I work for one of the few remaining brick and mortar tech shops in my area and we had a meeting with the owners a couple weeks ago. We were all prepared to tell them that we were unwilling to sell or support Windows 8 any further. To our joy they gave us those very instructions. You should have seen the smiles spreading around the room. And we are not the only ones snubbing 8. Three other shops in this area are doing the same. It was left to me to inform the MS reps of the news. Funny thing, when I did they weren't at all surprised. They didn't argue or try to talk us out of it. They simply said they'd be happy to continue supplying us with 7. I asked one of them why they didn't put up more of an objection. He answer said it all; "You're not the only company to take this position. We know that 8 is not well received or liked". When Microsoft's own reps are talking like that you just KNOW something's wrong. I think I'll leave it at that.

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