Intel Haswell-E Overclocking

One of the burgeoning questions relating to overclocking over the past couple of years has been the quality of Intel’s construction under the heatspreader relating to thermal interface material and adhesives. This caused enough of a talking point for Intel to release Devil’s Canyon (read our review here) which featured an upgraded interface and essentially reduced the thermal pressure restricting the overclock.

Thankfully Intel has not decided to play around with the extreme edition platform too much since Nehalem. Although recent reports suggest that Intel is using an epoxy to bind the die to the heatspreader, one tell-tale sign that a goopy TIM is not being used is the hole in the heatspreader in one of the corners.

Looking through the previous generations, Sandy-E, Ivy-E and Haswell-E shows this hole, which is typically thought to allow for expansion of the heatspreader and/or gas trapped inside due to the heat. Also due to the way that the epoxy is handled, the heatspreader cannot be removed without force and destroying parts the silicon die.

Due to the way that the CPU is arranged, with the cores to the left and right of center, there may develop a series of recommendations when using different methods of applying thermal paste as the sources of the heat will most likely be in these two regions. I would advise the normal procedure of applying thermal paste here: a small blob in the middle and allow the heatsink to spread the TIM through applied pressure. This helps remove air bubbles as the TIM spreads; spreading it out manually leads to air bubbles all over the place and is not recommended for high thermal sources.

In our results below we are using a Cooler Master Nepton 140XL closed loop liquid CPU cooler, and following the instructions above our CPU temperatures stay extremely low until we pile on the overclock. In fact I was seeing less than 30ºC while idle, which should bode well for overclocking.


Our standard overclocking methodology is as follows. We select the overclock options and test for stability with PovRay and OCCT to simulate high-end workloads. These stability tests aim to catch any immediate causes for memory or CPU errors.

For manual overclocks, based on the information gathered from stock testing, we start at a nominal voltage and CPU multiplier, and the multiplier is increased until the stability tests are failed. The CPU voltage is increased gradually until the stability tests are passed, and the process repeated until the motherboard reduces the multiplier automatically (due to safety protocol) or the CPU temperature reaches a stupidly high level (100ºC+). Our test bed is not in a case, which should push overclocks higher with fresher (cooler) air.


Due to the timing of our testing, we were only able to test two i7-5960X CPUs. Both of these were M0 stepping samples, the same as the retail stepping as far as we understand. The i7-5960X for reference is a 3.0 GHz base clock CPU with 8 cores, with a stock load voltage around 1.050 volts. Standard turbo modes allow 3.5 GHz, and so we start our testing at 3.5 GHz on all cores at 1.000 volts set in the BIOS. Where load line calibration was possible, it was enabled to match our setting as closely as possible, but otherwise only the CPU voltage was adjusted.

The first sample has a lot of early headroom with +0.100 volts allowing for an extra +1.1 GHz, or a 36.7% overclock. It has been a long while since numbers like +36.7% has been bandied around Intel’s extreme range, with only the i7-920 type Nehalem CPUs doing that sort of overclock in its stride.

The sweet spot for this CPU seems to be at around 4.4 GHz where the CPU voltage is just starting to rise but peak temperatures are under 75ºC.

Unfortunately our second sample was pretty much a dud by comparison. The voltage needed early on in the overclock went up quickly. This time we were unable to monitor temperatures due to a BIOS issue, but had a power meter on hand. We still managed a +1.1 GHz overclock easily enough, although +0.175 volts was required.

At 4.1 GHz, peak power is +104W over the system power draw at stock, with another 40W at 4.3 GHz. This shows that Haswell-E can be a power hog from even small overclocks, and thus users must have cooling to match. If we add the 140W TDP and the +140W more from the overclock (it would most likely be more than this due to the change of efficiency in the PSU curve), then a mildly overclocked CPU is fast approaching 300W. One can imagine that a highly clocked 4.7 GHz sample would be nearer 400W, and thus users should purchase power supplies to match.

A Problem with Haswell

One issue from Haswell does crop up with Haswell-E: the variability in the quality of the processors. Intel only guarantees that the processor will run at the specific frequency and voltage that is applied out of the factory: any other speed is out of specification and not supported. With Haswell LGA1150 CPUs, while the turbo frequency of the i7-4770K was 3.9 GHz, some CPUs barely managed 4.2 GHz for a 24/7 system.

If we consider that the i7-4770K only needs one of those CPU cores to be below quality to ruin overclockability, then placing double the cores on the i7-5960X is asking for double the trouble. Time to put some numbers to this:

In ASUS’ press deck for overclocking recommendations that came with the X99-Deluxe, they tell us the following:

i7-5960X at 4.4 GHz with 1.300 volts is below average
i7-5960X at 4.5 GHz with 1.300 volts is average
i7-5960X at 4.6 GHz with 1.300 volts is above average

By that standard our first CPU is around average and the second CPU we tested is below average. Even with these guidelines, it would seem that other reviewers and even manufacturers are getting a wide array of results. I have heard of reports of CPUs getting 4.7 GHz on a water loop, whereas others are testing a range of CPUs and not getting more than 4.4 GHz, like our second sample.

ASUS is recommending that anything over 1.25 volts requires a water/liquid cooling as a bare minimum, with up to 1.35V needing a triple (3x120mm) radiator setup depending on ambient temperatures. As with most overclocked setups, this means that the enthusiast user must decide between clock speed or fan noise for their machine.

Another issue with Haswell-E is the current draw of the CPU. ASUS is stating that the standard current draw for the CPU can reach 25 amps, meaning that the power supply must be capable of supplying at least 30 amps on the EPS12V cable. This is covered for most home-build non-OEM power supplies with an 80 PLUS rating, but suggests that a cheap power supply might trigger the over-current protection early.

Comparison to Ivy Bridge-E, Sandy Bridge-E, Haswell

As part of our testing, we hooked up our older i7-4960X and i7-3960X to the ASUS Rampage IV Black Edition, as well as compared to our previous i7-4790K Haswell overclocks:

Our i7-3960X sample at the time was actually a really nice overclocking CPU, in comparison to our i7-4960X which was below overage. I put two values here for the i7-5960X, showing that a 4.3 GHz overclock, while it is lower in number than the 4.8 GHz of the i7-3960X, is actually around the same percentage overclock. If we have a good i7-5960X for comparison, then +50% overclock comes very easily.

The next question then is which one is better for performance?  While the Haswell-E CPUs have a lower frequency than the previous generations, they do have the benefit of a higher IPC and DDR4 memory. There is also the core count, with the i7-5960X having 8 cores at 4.3/4.6 GHz against the six cores or four cores.

It should be obvious that for single core throughput, the i7-4790K wins at 4.7 GHz:

Kraken 1.1, Overclocked Results

FastStone Image Viewer 4.9, Overclocked Results

Dolphin Emulation Benchmark, Overclocked Results

3D Particle Movement: ST, Overclocked Results

In most benchmarks, the 5960X, 4960X and 3960X are actually evenly matched for single threaded performance, with the 5960X taking the edge on software that can take advantage of the newer instruction sets.

For multithreaded tasks, an overclocked i7-5960X is the only way to go:

HandBrake v0.9.9 2x4K, Overclocked Results

Agisoft PhotoScan - Total Time, Overclocked Results

Hybrid x265, 4K Video, Overclocked Results

The graphs later in the review comparing each of these processors at stock will have our overclocked results as well.

Evolution in Performance: IPC and Memory Bandwidth Power Consumption, Test Setup
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  • MrBungle123 - Friday, August 29, 2014 - link

    Is there anything but 'edge case' justification for upgrading any more? PCs used to be exciting because things were always changing, this is just getting boring.
  • edzieba - Friday, August 29, 2014 - link

    VR. The frame rendering time requirements are pretty stringent. This is more on the GPU than the CPU for graphics, but you want to try and keep physics tics at a good rate to prevent objects jumping around the world.
  • tech6 - Friday, August 29, 2014 - link

    Even the 'edge case' is not longer a slam dunk as most workstation workloads like CAD do very well on the 4960X.

    The only real cases are heavy scientific number crunching, animation rendering and cracking password hashes by brute force.
  • MrBungle123 - Friday, August 29, 2014 - link

    It used to be that if you were 2 generations behind your system was so slow and irrelevant that you just couldn't run modern software at anything approaching an acceptable level. Now we have a situation where ancient systems on X58 (circa 2008) are still close enough in performance to the extreme high end in 2014 to not only be in this review but also fit somewhere into the top half of the product stack of modern Haswell based hardware.

    If you compare a top of the line Nehalem chip to its equivalent from 6 years prior (a Northwood core P4 from 2002) it would make a mockery of 8 of them at the same time. This article is saying a 31% jump from Nehalem to Haswell-E -- that kind of performance increase (as a percentage) would have amounted to 2 or 3 months worth of clock speed bumps at any other time in the history of PCs.
  • wireframed - Friday, August 29, 2014 - link

    Somewhat true, but consider that you get 30% IPC increase, 25-30% frequency increase and a 50% core-count increase, and it adds up to around a 100% increase in performance.

    Granted, 100-110% over 6 years is hardly impressive compared to earlier, but there isn't that much low-hanging fruit.
    Also, the mainstream which drives revenue is, as you point out, largely content. They're looking at adding devices like tablets and consoles, instead of upgrading their computers. That probably plays into the amount of R&D Intel decides to spend on the HEDT platform.
  • Kain_niaK - Friday, August 29, 2014 - link

    Exactly exactly exactly! I am still on X58 with a i7 990x. I don't play much games any more but even to play the newest games ... I do not need to upgrade my CPU and have not needed to upgrade my CPU since 2010. And even my i7 975x or a i7 920 from 2008 would still be more then fast enough. Then music. I use my system mainl as Digital Audio Workstation. Most of my plugins and music applications support multithreading. I cannot realistically ad so much stuff to a project that it maxes out the CPU. And rendering time? Who cares, most of my renders are done before I am done playing chess on the toilet anyway. Then overclocking. The i7 920 and anything on X58 was great. After that ... the fun and the excitement kind of went away and has never come back. What's the SUPERPI MOD record these days? I have not heard about any significant record breaking for a long time. Back in 2008, 2009,2010 I was hearing news about famous new overclock records. After that, it stopped. Let's face it. We hit a clock limit and for a breaktrought in singlethreated speed ... it's just not gonna happen until some genius designs a totally different system. Probably not using electricity but light. But that's like 20 years away because you don't just start over. All we have been doing is improving old technology not inventing something completely new. We are hitting the limits of nature ... so all the geeks and the nerds will just have to way at least another 10 years before we get to the exciting stuff again.
  • MrBungle123 - Friday, August 29, 2014 - link

    At this rate 10 years from now any Haswell i7 is still going to be within spitting distance of whatever the best is. lol

    If you wan't Skylake performance today OC your Haswell by 250MHz, Ivy Bridge by 400MHz, or Sandy Bridge by 600MHz.
  • Laststop311 - Saturday, August 30, 2014 - link

    it wont be the cpu performance difference that makes u upgrade it will be the new features. Skylake will have pci-e 4.0 and usb 3.1 and then chipsets after that will add more new things faster storage standards and who knows what else.

    I was already in this position. The speed of the i7-980x was still rly good. Got mine oc'd to 4261mhz. But guess what on x58 you get not pci-e3.0 no sata 3 no usb 3.0. These features have become very standard. You also get no sata express or pci-e ultra m2 which will soon be commonplace as well as no quad channel memory and no ddr4. All the missing features made me upgrade, not the speed. Similar situations in the future will cause people to upgrade every 4-6 years.
  • TiGr1982 - Tuesday, September 2, 2014 - link

    You can still plug the PCIe USB 3.0 extension board there and get at least 2 USB 3.0 ports on the back of the case, to somewhat mitigate the age of the platform.
    But, with PCIe 2.0 and SATA 2, one is stuck, indeed.
  • actionjksn - Saturday, August 30, 2014 - link

    Nehalm was great, but the last big bump was really Sandy Bridge. After that, not so much. This is actually a big concern for the processor makers. The technology and the silicon itself is reaching its limits as far as making significant gains on the next generations. They were getting big performance gains from just die shrinks alone, but those days are over. And how much more can they shrink them? It's getting harder all the time, they may get to 7nm to 10nm.

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