Despite being an integral part of Intel's product stack, reviews of the lower power models are few and far between. For those of us that have no interest in overclocking, the lower power parts can offer similar stock performance to the big boys but at 65W and 35W. Today we are testing three chips available from Newegg at $135, $215 and $315.

Not All CPUs are Alike

While Intel's CPU naming scheme is finally starting to make sense to home system builders, their product stack consists mainly of generic numbers in either Celeron, Pentium, i3, i5 or i7 format unless someone sits down and explains the trend to the individual. These models are clearly defined whereby a bigger number tends to mean more frequency. With this general stack of names, there are sometimes models that come with extra letters. Overclockers already know the K and the X models as having their multiplier unlocked for extra potential, but for other CPUs we have T and S destinations. (Xeons also use the letter L, and mobile chips have H/Y/U.)

Simply put, T is used for 35W/45W models and S is for 65W models. The S models tend to have similar single core performance to their normal cousins, but reach 65W by reducing the multicore frequency when the CPU is loaded. The T models reduce both single core and multicore frequency to hit their 35W or 45W, but tend to be a little more esoteric in their position in the stack.

In general there are two ways to reduce the TDP on a CPU. We can either reduce frequency (easy) or reduce voltage (difficult). Reducing the voltage results in more of a change in power consumption, but the best way to tackle this is when Intel performs its binning process.

When a manufacturer creates a wafer of CPUs, these have to be tested for accuracy of calculations, functions, and the voltage/frequency response. It is this latter characteristic which matters most when determining what product in the stack it should be. The units with the highest frequency for the lowest voltage (on a scale) tend to be reserved for the fastest processors or Xeons. Note that it is not only a single data point being tested, but a whole scale from low frequency to high frequency. The unit has to match an entire line to be sufficient for that designation. Where the low power CPUs come in is that they follow a particular line at a potentially lower voltage range than expected.

There have been reports of the regular branding of CPUs being reduced in frequency and matching the stability of the S/T processors. That is entirely possible, as a unit can be a member of many bins at the same time. At the end of the day, when you purchase a lower power processor, you are essentially guaranteed that level of performance and TDP by the processor manufacturer.

The Product Stack

To represent Intel's Haswell line-up, I want single out where the S and T processors stack up against their normal counterparts. Thus is made somewhat difficult by the Haswell refresh earlier this year which caused a frequency bump in most models, but both pre-refresh and post-refresh processors are still up for sale in most markets.

Intel Haswell T CPUs
  Cores / Threads TDP L3 Base
Frequency
Turbo
Frequency
OEM Price
i3-4130T 2 / 4 35W 3MB 2900   $122
i3-4150T 2 / 4 35W 3MB 3000   $117
i3-4160T 2 / 4 35W 3MB 3100   $117
i3-4330T 2 / 4 35W 4MB 3000   $138
i3-4350T 2 / 4 35W 4MB 3100   $138
i3-4360T 2 / 4 35W 4MB 3200   $138
i5-4460T 4 / 4 35W 6MB 1900 2700 $182
i5-4570T 2 / 4 35W 4MB 2900 3600 $192
i5-4590T 4 / 4 35W 6MB 2000 3000 $192
i5-4670T 4 / 4 45W 6MB 2300 3300 $213
i5-4690T 4 / 4 45W 6MB 2500 3500 $213
i7-4765T 4 / 8 35W 8MB 2000 3000 $303
i7-4770T 4 / 8 45W 8MB 2500 3700 $303
i7-4785T 4 / 8 35W 8MB 2200 3200 $303
i7-4790T 4 / 8 45W 8MB 2700 3900 $303

 

Intel Haswell S CPUs
  Cores / Threads TDP L3 Base
Frequency
Turbo
Frequency
OEM Price
i5-4430S 4 / 4 65W 6MB 2700 3200 $182
i5-4460S 4 / 4 65W 6MB 2900 3400 $182
i5-4570S 4 / 4 65W 6MB 2900 3600 $192
i5-4590S 4 / 4 65W 6MB 3000 3700 $192
i5-4670S 4 / 4 65W 6MB 3100 3800 $213
i5-4690S 4 / 4 65W 6MB 3200 3900 $213
i7-4770S 4 / 8 65W 8MB 3100 3900 $303
i7-4790S 4 / 8 65W 8MB 3200 4000 $303

If we do direct comparison with a few of the S processors with their non-S counterparts, we see their main difference is just the multicore frequency to drive the TDP down.

Intel Haswell S CPU Comparison
  Cores / Threads TDP L3 Base
Frequency
Turbo
Frequency
OEM Price
i5-4590S 4 / 4 65W 6MB 3000 3700 $192
i5-4590 4 / 4 84W 6MB 3300 3700 $192
i7-4770S 4 / 8 65W 8MB 3100 3900 $303
i7-4770 4 / 8 84W 8MB 3400 3900 $303

With the T processors, we see a more aggressive trend especially with the i7 range.

Intel Haswell T CPU Comparison
  Cores / Threads TDP L3 Base
Frequency
Turbo
Frequency
OEM Price
i3-4160T 2 / 4 35W 3MB 3100   $117
i3-4160 2 / 4 54W 3MB 3600   $117
i7-4770T 4 / 8 45W 8MB 2500 3700 $303
i7-4770 4 / 8 84W 8MB 3400 3900 $303

The i7 35W processors have always been a fascination of mine (much like the 65W 12-core Xeon we reviewed earlier in the year). Ultimately these are best for work flow that can use multicore processing but the code has significant memory delays. This reduces the idle time per core and uses less power.

The purpose of this review is to see how these processors compare to those we have already tested. We currently have a good spread of the Haswell range, and all the results can be found in our online benchmark comparison database, Bench.

Test Setup

Test Setup
Processor
Intel Core i3-4130T 35W 2C/4T 2.9 GHz
Intel Core i5-4570S 65W 4C/4T 2.0 GHz / 3.0 GHz
Intel Core i7-4790S 65W 4C/8T 2.7 GHz / 3.7 GHz
Motherboards ASUS Z97 Pro
MSI B85M Eco
Cooling Cooler Master Nepton 140XL
Power Supply OCZ 1250W Gold ZX Series
Memory G.Skill RipjawsZ 4x4 GB DDR3-1600 9-11-9 Kit
Memory Settings 1600 9-11-9-27 1T tRFC 240
Video Cards MSI GTX 770 Lightning 2GB (1150/1202 Boost)
Video Drivers NVIDIA Drivers 337
Hard Drive OCZ Vertex 3 256GB
Optical Drive LG GH22NS50
Case Open Test Bed
Operating System Windows 7 64-bit SP1

Load Delta Power Consumption

Power consumption was tested on the system while in a single MSI GTX 770 Lightning GPU configuration with a wall meter connected to the OCZ 1250W power supply. This power supply is Gold rated, and as I am in the UK on a 230-240 V supply, leads to ~75% efficiency > 50W, and 90%+ efficiency at 250W, suitable for both idle and multi-GPU loading. This method of power reading allows us to compare the power management of the UEFI and the board to supply components with power under load, and includes typical PSU losses due to efficiency.

We take the power delta difference between idle and load as our tested value, giving an indication of the power increase from the CPU when placed under stress.

Power Consumption Delta: Idle to AVX

Power consumption for our i3 and i5 samples were near on the mark, whereas the i7-4790S scored 102W from idle to AVX. This is more than the i7-4770K, which might come across as a bit alarming.

We also have some full system power draw numbers from the MSI B85M ECO review, while using a Rosewill Silent Night 500W Platinum power supply. These are still in the 5% power used range for the unit, so efficiency is still around 70-80%.

Power Consumption w/Integrated Graphics

Load Delta Temperature on Intel Stock Cooler

At request from some of our readers on Twitter, we also measured the temperature delta from idle to load on the stock Intel cooler.

Temperature Delta: Idle to AVX

CPU and Web Performance
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  • eanazag - Thursday, December 11, 2014 - link

    That would directed at Ryan Smith and maybe jarred Walton for the mobile side of the equation. I suspect that the mobile side is unaffected at the moment.

    The only card that is well supported by all the new features in Omega is the R9 285 (Tonga). The R9 290 and 290X make a decent showing but are missing the 4K virtual resolution support.
    Reply
  • chekk - Thursday, December 11, 2014 - link

    Based on some other reviews, I was starting to think Anandtech had switched back to separate power consumption idle and load numbers, but here we go again. Please stop.
    The audience here is enthusiasts and enthusiasts want the complete picture.
    Reply
  • DiHydro - Thursday, December 11, 2014 - link

    I agree, if I have a server that is idle most of it's life, I want to know how many watts it is drawing at idle. On the other hand, if it is running 100% 24/7 then I want to see if a higher TDP, better performing CPU will be cost effective over a cheaper lower TDP part that might run a task longer. Reply
  • alacard - Thursday, December 11, 2014 - link

    Xbitlabs did an excellent write up on the 4670S and T variants. Idle results for those can be found here: http://www.xbitlabs.com/articles/cpu/display/core-...

    Ultimately extremely disappointing results. Intel couldn't even be bothered to do the bare minimun and bin these chips for better perf/watt. Pathetic.
    Reply
  • TiGr1982 - Thursday, December 11, 2014 - link

    Captain Obvious tells us all, that Intel has a very weak competition on the x86 CPU front in all the recent years (I would say, right from the launch of Sandy Bridge LGA1155 almost 4 years ago). So, they make big money "for free" (in a sense that it's an easy money for them) all these years and don't have to bother about such peculiarities as better perf/watt... Reply
  • Khenglish - Thursday, December 11, 2014 - link

    That xbitlabs review is very good and what I would have liked to see done here.

    Yeah bad results. I was hoping that these new parts meant that intel improved haswell's power efficiency, but in reality they just lowered the TDP.
    Reply
  • smilingcrow - Thursday, December 11, 2014 - link

    This feels like almost a completely wasted review, a sort of Seinfeld review; a review about nothing.
    Most things you can surmise about these S chips as many things scale linearly so it would have been good to have seen a much better focus on power consumption.
    The unanswered question is whether these chips use different voltages than the stock chips and also a lack of hard power data; the delta data is not enough.
    Also what did you use to load the cores?
    It says AVX but what application and is AVX a good example to use as how many applications use it?
    I’d like to have seen a focus on different CPU loads to determine the different characteristics of these S chips; INT, FP, AVX.
    So rather than the multitude of redundant data that can deduced from scaling of frequency why not something focused and new!
    What a wasted opportunity and a poorly thought out review.
    Reply
  • theKai007 - Thursday, December 11, 2014 - link

    Intel announced the Intel IoT Platform, a reference model end-to-end designed to unify ans simplify connectivity and security for the Internet of Things. http://bit.ly/1yCMSnB Reply
  • name99 - Thursday, December 11, 2014 - link

    Look at the partners.
    Looks more like a enterprise software "solution" to acquire/store/extract data from than actual hardware or anything of interest to normal folks.
    As long as Intel's HW story in that space is Quark, forget it...
    Reply
  • xeizo - Thursday, December 11, 2014 - link

    Right on spot, I use a 4570S in my Linux home server. But as an enthusiast I did some bclk(couldn't resist it) to 106.4 so that it Turbo:s to 3.83GHz and multithreadsx4 to 3.4GHz ;-) Anyway, it feels very fast running Linux. I couldn't have used a K-processor as I wouldn't be able to resist maximum clock it, no power saving server ...

    Gaming is done on a 4.8GHz 2600K, it doesn't look like a need to replace it anytime soon. Unless Skylake surprises us all.

    Nice job informing about those lower power cpus, saves us time from undervolting and just draws less power from day one.
    Reply

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