Intel Haswell Low Power CPU Review: Core i3-4130T, i5-4570S and i7-4790S Tested
by Ian Cutress on December 11, 2014 10:00 AM ESTHaswell Low Power CPU Conclusion
There is a clear demand for lower powered everything, as long as the performance is still there. We saw this with the MSI B85M ECO motherboard we reviewed recently, whereby as long as it makes financial sense as well it becomes a win-win.
Intel ultimately keeps its binning and testing process secret, but it is the binning process that allows them to keep high yields by a partitioning off defective cores or CPUs that do not conform to the best voltage/frequency curves. Some CPUs will fall into multiple bins, allowing Intel to sell the unit as a model that needs a boost in stock due to consumer demand. This is why some processors can perform as well as others in terms of their voltage/frequency response, but the only way to guarantee a certain level of performance is to buy the exact processor you need.
Today we tested three processors: the i3-4130T, the i5-4570S and the i7-4790S. These tackle three competitive price points on Newegg at $135, $215 and $315. This is the main reason we requested these processors in rather than others, as many S or T models end up as OEM only. The OEM only models sometimes appear for sale depending on the retailer and their own stock levels, or the region, but are not available everywhere. This is a shame, as some real gems (like the i7-4765T) are on Intel's road map.
The S processors command nothing extra over the base cost, in comparison to the premium of the K models. In terms of performance, in single threaded benchmarks (and therefore responsiveness) these CPUs performed the same as their counterparts, and our i7-S CPU was right on the money all the way through. Particularly in our gaming benchmarks, no performance was lost against the bigger models. In mutlithreaded benchmarks, there was a slight performance decrease. This means a Google Octane result down from 33512 with the i7-4790 to 31127 with the i7-4790S, a loss of 7% in exchange for the reduction in TDP, but in our gaming benchmarks the only real deficit afforded by the S/T processors was that in a few circumstances, minimum frames were lower, such as Bioshock Infinite moving from 28.0 FPS on the i3-4360 to 24.5 FPS on the i3-4130T.
With the T processors, the cut is more severe, especially for the i7 models. For our i3 T processor, we are reducing down from a 54W base component to a 35W, similar to the i7 S reductions. As a result, the benchmark numbers, while lower, are comparable to those i3 models with a potential sticker saving of 19W.
Is the power reduction worth the increase in cost? Ultimately the main use for lower power processors is for systems where heat and noise are critical junctures in the design. By using a lower power processor, the heatsink can also be smaller. This means certain office designs and machines destined for communal areas of the home are the main target points, as well as potential servers that end up locked in a room somewhere. Intel's range of lower powered Haswell processors, according to their road maps, is quite substantial, although one downfall for end users is that some of the exciting parts are OEM only.
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azazel1024 - Thursday, December 11, 2014 - link
Can we also move away from having a GPU in the system for tested idle and load power consumption? It is one more source of bluring on what is actually using the power. Everything on the chart has an iGPU and in most cases businesses or low power users are going to be leaning on the iGPU, not a dGPU. So seeing what system power consumption is without a dGPU is important, even if all systems have the same contribution from an identical dGPU (it means a lot more if the dGPU is contributing 10w at idle...so suddenly you have a 3w difference between processor models...but the idle is 10w for one and 13w for another, instead of 20w and 23w).barleyguy - Thursday, December 11, 2014 - link
Delta charts are more accurate, and easier to generate, than absolute numbers. An absolute number will either be "total system power" or "total system power minus an estimate of non-processor power". The first is useless as information about the processor, because it isn't comparable across platforms, and the second is only an estimate unless hardware mods are done for power taps. For a chart that has such a large number of processors on it, the estimation errors for calculating discrete draw would likely put the chips in the wrong order.rootheday3 - Thursday, December 11, 2014 - link
For people who are using the onboard graphics, a 1250 power supply, even one that is Gold rated, is going to be pretty inefficient at low power.I know it is nice/convenient to have a single common setup for testing both with and without graphics and it makes things "apples-to-apples" but it doesn't match how I would build a system. If I really only intend to use the onboard graphics, I would try to pick a power supply that was sized appropriately.
For users trying to understand the platform/cpu idle and load power, it seems like it would be beneficial to have both idle and load power reported AND appropriately sized power supply for the test conditions.
Daniel Egger - Thursday, December 11, 2014 - link
> If I really only intend to use the onboard graphics, I would try to pick a power supply that was sized appropriately.Good luck with that. There're almost no appropriately sized PSUs for such systems available on the market; seems like they're all exclusively designed for and sold to big OEMs.
azazel1024 - Thursday, December 11, 2014 - link
Not really. The idle power of the CPU very well might be different between the different CPUs combined (which can be sussed out if they all use the same hardware configuration excepting the CPU). Idle to load might only be a 10w difference for one CPU...but it might idle using 20w for the CPU. Another CPU might be a 15w difference from idle to load, but it might idle at 5w...making it a much more power efficient CPU overall.rootheday3 - Thursday, December 11, 2014 - link
At idle, CPUs enter pkg c states and burn less than 1w regardless of sku/stepping/binningpiasabird - Thursday, December 11, 2014 - link
http://download.intel.com/support/processors/corei...It must be because intel is not selling the CPU's in boxed retail set. 4360T, 4350T, 4330T, 4160T, 4150T, 3250T are not available boxed, but are valid parts. My guess is you have to order them as tray and are only available to OEM's. However, they may be available through a small OEM custom computer builder shop.
sweetie peach - Thursday, December 11, 2014 - link
I have been using the i7-4790S for the past 4 months and there is something very strange about the results. The cinebench multithreaded bench is way too high. This cpu turbos to 3.6GHz with 4 cores so it can not possibly have the same score as a non-S that turbos to 3.8 GHz with 4 cores. Also my own average results are 160 for single and 740 for multi (HT enabled of course). Maybe there is something wrong with my setup but it doesn't feel slow in any way. It was very difficult to get hold of but it made sense because i want a very quiet computer even at load.otherwise - Thursday, December 11, 2014 - link
Do any of these support ECC? Or do you still need a sandy-bridge era i3 to get that feature?Cerb - Sunday, December 14, 2014 - link
Most, if not all, the Haswell Core i3 CPUs support ECC, as do all of the Xeon E3 V3 series.