Legit Reviews

Does anyone know what power they need ? I have had quite a long hunt on the net and have found answers like "not a lot" , "about the same as a nvid 520" and I've found power consumption figures for the total system on IGPU enabled rigs. I also note m/board options to increase IGPU voltage and one boast of 4 pwms devoted to the IGPU powerline. From what I've read the 4000 series uses less than the 3000 but no figures. If anyone can point me in the right direction my thanks in advance . I'm sure the truth is out there somewhere.

Well it's built into the processor, so there is no way to really tell what just the GPU uses. That is why you don't see this number out there any place as it is not given by Intel and there it no way to find it out on our own.

Apoptosis wrote:Well it's built into the processor, so there is no way to really tell what just the GPU uses. That is why you don't see this number out there any place as it is not given by Intel and there it no way to find it out on our own.

Thank you, yet the IGPU voltage can be set externally and although "built in" it uses no power if unused- gated off?- or is it built on?
If I take the power draw on the mains with out a display from an underclocked i5 2550k and a i5 2500k and do it again with a discrete graphics card it could be interesting.

parts of the iGPU will shut down when disabled, but it's not entirely turned off and still uses power.

If I take the power draw on the mains with out a display from an underclocked i5 2550k and a i5 2500k and do it again with a discrete graphics card it could be interesting.

That test would work, but each processor has different leakage and depending on where it came from on the wafer it will vary in power usage. Far more than the 0.008V you noted in our review. You also have to have a dGPU with the 2550K, so you'll never really get a true number. I guess you can turn the system on without a dGPU in the 2550k system and take the power reading where the post screen is or enter the BIOS.

As stated, you're never going to get the real figures.
Intel will never release such things as it could give the competition an idea how they implemented it.
Intel has it's PMM unit(s) built in to the chip. This dynamically manages power usage, C-States, Speedstep etc.
While this works slightly differently depending on the chips Tjmax (even when the same model & TDP), it's not that smart.
It works using when usage hits a given, preassigned limit. With "bad" chips, this limit might be set one level lower. (I'm not just talking turbo, but also power gating & more)

Your best bet is to wait for someone to release some Windows software which interacts with the software hooks/registers Intel made available. Since it hasn't happened already, it's likely it's either not acurate or just not worth it.

Checkout lesswatts.org, it's all about powersavings with Intel and Linux; but you might find some documentation there.
There's plently on the older gfx, chip set based ones.