Originally Posted by lacrossewacker
Originally Posted by keiths
I don't get why the things are power hogs.
This isn't exactly how you should measure power use, but take a look at this.
2700k has a TDP of 95 watts. Using some rudimentary math, divide that by 4 and you have a TDP of 23.7 watts per core (I know this isn't really how it works, but stay with me)
Now take a look at a 3930k.
3930k has a TDP of 130 watts. Using that same math, divide that by 6 and you have a TDP of 21.6 watts per core
In essence, it looks like the 3930k is actually using less power per core (based on the assigned TDP)
how this compares in real life usage, I'm not sure, but it has 6 cores vs the mainstream i7's 4, so expect 50% more power usage.
Not quite, both of you. First of all, Intel has most probably decided to stay on the safe side and adopt a 130w TDP for IB-e for the same reason that they initially stated that IB would have a 95w TDP, so motherboard makers wouldn't cheap out, since it's supposed for those motherboards to also support SB.
We all know at every opportunity vendors could try to pull a trick like this, make boards that would only work properly with 77w TDP CPUs and then the consumer would be left with a myriad of boards to chose from and a big confusion, which Intel wants to avoid.
The same thing can be said for the X79 platform, the motherboards are supposed to be able to handle both SB-e and IB-e.
I'm fairly sure that the i7-4820K could have a 95w TDP if Intel wanted and the i7-4930K could have a 105w TDP (just like the first stepping of the Q6600), but that would only introduce factors that Intel wants to avoid. First of all, motherboard makers might have tried to make cheaper entry level boards for the i7-4820K, but that would be bad for Intel and eventually the consumer as that would hurt the upgrade perspective. Secondly, having different TDP numbers for different chips in the same enthusiast space is also bad for certification of cooling / cases, etc. Back in the Pentium 4 days each new speed had a different TDP, now Intel prefers to standardize.
As to what each core uses for power, don't forget that the 1155 / 1150 CPUs have an integrated GPU, so the TDP factors it in, the X79 CPUs don't have an integrated GPU, but they do have more cache, a memory controller with twice the channels and validated to work at higher speeds along with a PCIe controller with more than twice the lanes. When the i7-3820 was reviewed it used more or less the same power as the i7-2600K, slightly more at times, but it did also perform better in single and multithreaded scenarios thanks to its higher clockspeed and larger cache and more memory channels, now if you were to use the i7-2600K's integrated GPU while benchmarking, I'm sure the i7-2600K would use more power, so when you look at TDP, don't forget that 1. you might not be the least close to it because you're not using the built-in GPU, 2. you might not be close to it because of the standardization Intel decided to apply for simplicity's sake.Edited by tpi2007 - 8/2/13 at 8:27am