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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patrickjchase - Friday, December 12, 2014 - link
I used to work on SoCs in process nodes down to 28 nm, and the variation from the fast/fast (low-delay, leaky) to the slow/slow (high-delay, low-leakage) corners in modern processes is substantial. The fact that a given vendor isn't binning simply means that they're adding a fair bit of margin.For that matter I wouldn't be so sure that Apple doesn't bin. For example it's possible that the A7s in iPhone 5s and iPad Air were binned differently.
Finally, Intel's volumes create additional binning opportunities. A process condition that happens, say, 0.1% of time time would constitute such as small volume as to be useless to most vendors but adds up to a nice niche for Intel.
aj654987 - Friday, May 15, 2015 - link
I think its reasonable to believe they are binned. From a business perspective, is it really necessary to have THAT many different CPU models that Intel has? At some point you can have too many products and theyre competing with each other. Look at GM and how they had too many brands and rebadged vehicles that are competing with each other. I dont think there IS any business advantage to artificially create as many different chip models as intel has, though there is a business advantage to being able to salvage chips they would otherwise have to toss.When comparing to ARM processors, those are less complex and less expensive. If they have an ARM chip that tests bad, it may make more sense to toss it then to cripple it and sell it as a lower model. Also like consoles there is a preference to have the same speed across all devices, where as with a PC, different CPU speeds seem more acceptable to the market.
eanazag - Thursday, December 11, 2014 - link
The 65W parts seemed to show increased performance in IGP gaming versus their non-S counterparts. 4790S vs 4790. I would suspect the TDP budget for the IGP is unaffected by the TDP reduction and therefore might get a little thermal room to run harder. Looking at Intel ARK the 4790 series all runs at 350 base and 1.2 max; the 4790K is able to boost higher to 1.25GHz. The IGP gaming number seem to tell this story.You can also see when a discrete GPU is thrown in there the non-S parts then perform above the S parts in gaming.
For IGP gaming AMD is still the best choice; and that is about all they're good for.
evilspoons - Friday, December 12, 2014 - link
This is the story in thermally-limited situations like the Surface Pro 3. The i5 model is faster at games than the i7 simply because the i5's CPU uses less of the thermal budget so the iGPU can stay faster for longer. In a more extreme case, running old non-CPU bound games (World of Warcraft), the i3 model is even better - the CPU leaves even more room for the iGPU.Of course, this could all be avoided by the game simply going "hmm, which one is really slowing me down - the CPU loop or the GPU loop?" and then throttling one to match, but the odds of that happening any time soon are pretty poor.
mortenelkjaer - Friday, December 12, 2014 - link
IGP gaming, What is that?MrSpadge - Thursday, December 11, 2014 - link
No. The regular Intel 22 nm CPUs are so good that they can run ~4.0 GHz at ~1.0 V, whereas stock gives them almost 1.2 V at the top turbo bin. So cutting down on power consumption hardly requires any effort.Samus - Thursday, December 11, 2014 - link
Eventually wear and leakage will cause tapering. The long-term reliability is Intel's goal which is why these chips are so conservatively clocked. I've already read reports of people running Haswell at 1.3V that initially had them stable at 4.6+GHz and a year later, can't crack 4.2GHz at 1.2V.Keeping these things around 1.0V is key to their service life. As Spadge said, try to get the most you can out of the stock voltage (usually 4GHz, sometimes more.)
B3an - Thursday, December 11, 2014 - link
Completely off topic, but you guys do an article on AMD's new "Omega" driver? It has loads of new features and i can't find anywhere that's done a proper in-depth article on it.DiHydro - Thursday, December 11, 2014 - link
The Tech Report, and PCPer both have articles about the features and performance gains of the Omega driver release.JarredWalton - Thursday, December 11, 2014 - link
It's in the works. Ryan and I both were out for a few days due to illness, unfortunately.