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.
Facebook
Twitter
RSS
76 Comments
View All Comments
Gowan08 - Thursday, December 11, 2014 - link
I am happy to see these CPUs doing so well for the price. I used the i5 S for a whitebox esxi server build and I couldn't be happier. I ended up building 2 as a way to get to VSAN in my home. the low power consumption works when you are planning to leave the server running for long periods of time. Rock solid processor.StrangerGuy - Thursday, December 11, 2014 - link
As somebody with a stock 4790K I have completely no idea just *what* exactly is the point of these new chips. It doesn't save any power over regular Haswells with regular consumer workloads when cores simply idle while sacrificing significant performance for insignificant power savings for heavy CPU loads.Daniel Egger - Thursday, December 11, 2014 - link
That's interesting, the numbers tell exactly the opposite and many people would argue the other way round that the little bit extra in performance for special cases (SLI setups, HPC, ...) is not worth the additional energy use at idle and load and even less the additional noise for the more capable cooling system.Peter Cordes - Friday, March 27, 2015 - link
They all use the same power at idle. The lower TDP processors make it safe to use a weaker fan or put them somewhere with worse airflow, even in the worst case when something does load the CPU for an extended duration.This and the xbitlabs article someone else linked show that the low-power variants behave the same as the regular versions, except for throttling down out of turbo sooner or farther under extended load. They are NOT more energy efficient, either in the CPU or the IGP.
HPC is the use-case where these lower TDP chips are exactly the opposite of what you want, unless you're really constrained by cooling, or your workload is actually constrained by memory latency but your CPUs are ramping up to max speed anyway.
Cerb - Sunday, December 14, 2014 - link
It does indeed save power, and the review shows exactly that. That is in fact the entire point. 84W may be too high for some scenarios, so there is a demand for CPUs with lower TDP. The Lenovo Outlet has several such PCs for sale at this very moment, that aren't much bigger than my unmanaged switch. I doubt an i7-4790K could be quietly cooled in such a small enclosure.bsim500 - Thursday, December 11, 2014 - link
These reviews are getting worse...1. I agree with the others. Please include separate idle & load power consumption. Include delta if you want *in addition* to not instead of.
2. Why on Earth would you attempt to review low-power CPU's on a 1250w PSU? This is a large part of the reason why there's only a 2w apparent difference between a 35w "T" and a 53w regular Pentium / i3 - at sub 5% loads the "+90% efficiency at 20-80% load" curve rapidly falls away to as low as 70%, even 60% on some PSU's. It can also add up to 20w to idle consumption which defeats the whole point of a low powered chip. The 35w "T" chips in particular are often used in slim TDP limited cases like the Akasa Euler (typically fed from an external 80-160w "brick" Pico-PSU / SFX PSU's or at most 360-400w Gold ATX (where a 70-80w load would be within the 20-80% load "90% efficiency sweet spot" of Gold PSU's)).
3. Idle to load delta power consumption (with no actual idle / load figures) is even worse than "delta only temps" and results in totally useless figures up to 20w out of whack for intended market (thin Mini-ITX) when it comes from a <5% load on a 1250w PSU that no-one would use on such chips. Again - PLEASE just show idle & load watts / temps in future.
4. The i3-4130T has been replaced (at same price) by the i3-4160T which is 200Mhz faster.
5. Is the Haswell +0.1v auto-overvolt on AVX Prime power virus load test really suitable for load testing on low-power CPU's which more than likely won't be fully loaded (or running constant load AVX apps)?
wintermute000 - Thursday, December 11, 2014 - link
"Why on Earth would you attempt to review low-power CPU's on a 1250w PSU?"THIS
BrokenCrayons - Friday, December 12, 2014 - link
I can kind of understand the PSU wattage. The same PSU has to be used across a lot of different system configurations ranging from very low demand hardware to extremely powerful, multi-GPU builds otherwise the results across the entire range become incomparable and possibly less valuable to readers. Then again, it has been a frequently mentioned sticky point for readers. Maybe branching out to a couple of PSUs that are of slightly more suitable wattage for their application would be useful. I think a lot of Anandtech readers, while very interested in tech reviews, aren't always looking for the very fastest and most powerful hardware available. The site does a really good job catering to that audience (I think so anyhow since sort of consider myself one of those kinds of readers who wants elegant, practical computing solutions instead of the biggest/fastest at any cost) with the exception of the PSU sizing problem you mentioned and the lack of absolute consumption numbers. But still, go easy on them. They have a lot of work to keep them busy and a lot of feedback to consider that might sometimes get conflicted between reader opinions.MrSpadge - Thursday, December 11, 2014 - link
The moderate binning should not require different CPUs. It would be nice if Intel simply used the already established tool of cTDP to offer users a choice. Run normally during winter and switch to power reduced mode in summer, or when a long video transcode is needed. Provide a simple app or windows switch for this. The Win Vista/7 gadgets would be ideal for this. Oh, and this software could be used on notebooks & tablets too, where it would be far more useful.Winterblade - Thursday, December 11, 2014 - link
This was just what I needed to read to convince myself of buying the Alienware Alpha base model :)