Intel Haswell i7-4770K IPC and Overclocking Review

Intel's clock keeps ticking and today lands on a "tock" in the development cycle. The new desktop Haswell processor represents a new microarchitecture built on the tried and true 22nm process technology that we have come to know and love with Intel's current Ivy Bridge microarchitecture. But what does Haswell mean for the computer enthusiast?

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Power Usage

Even though Haswell is covered here as a desktop launch, the architecture is truly focussed on the mobile market. When it comes to low power gates and states, Haswell is truly impressive. At stock clocks with on-chip video being used, our total system power at the wall was 32 watts at idle. Under our biggest loads (Prime95 and Handbrake) we saw usage at 108 watts. With our 4.8GHz stable settings, our system idled at 43 watts, and was using 186 watts under load. Watching the vCore scale down to 0.016v at idle is extremely impressive. Even more impressive is that you can watch it do this while idle and overclocked.

Sadly though, while the Haswell systems overall have been cool running, dumping all that overclocked heat out through the tiny area on top if the processor seems to be the enthusiasts’ problem.

How to Overclock Your Haswell Quickly

Again, I have only had experience so far with the ASUS Z87-A and Z87-Deluxe motherboards, but here is the simple procedure I have used on these two motherboards. I do need to say that it is very obvious that ASUS has put a tremendous amount of R&D into the auto-tune settings on its Z87 motherboards. I do have motherboards from Gigabyte and MSI that we will be getting to soon.

1. Enter the BIOS, set to Optimized Defaults.

2. On the Ai Tweaker screen, set the Ai Overclock Tuner to "Manual"

3. Set CPU Core Ratio to "Sync All Cores"

4. Set 1-Core Ratio Limit to "46"

5. Set CPU Core Voltage to "Manual Mode"

6. Set the CPU Core Voltage to "1.20"

7. F10, Save settings and reboot

If your system POSTs, loads up the OS, and is stable under stress, you just purchased a "good" CPU, or possibly have invested in LN2 cooling. If not, start working your way down multipliers and see where you finally get stable. This will give you some idea about the quality of your CPU in terms of overclockablity. Once you get this done you want to work your way up vCore voltage settings, check temperatures and stability then bump up the CPU clock multiplier and again checking stability; you can use ASUS Ai Suite III software from the desktop if you want or adjust in the BIOS. It only depends on your preference at this point as both functions work very well. How far up you can push the processor voltage up is going to directly depend on your cooling system. Once you see per-core temperatures get into the high 80s or 90s your overclock will very possibly get unstable. The latest version of Core Temp works to monitor per core temperatures as well as Aida64. I like the graphing feature on Aida64 stress test, which I showed in the screenshots on the previous page, but it takes up a lot of screen real estate.

Once you are done finding your CPU core overclock, you can start working on scaling the memory clocks and tweaking timings from default settings. You will very likely find good ground here simply using the XMP presets for your RAM if it has those.

Obviously there are a thousand more options to tweak with in the BIOS. ASUS has flat out told me, "Everything else has auto rules and YOU DO NOT need to adjust them." Of course you can play with the "usual culprits" in the BIOS that generally give us better overclocking. However after spending a lot of time overclocking this Haswell, ASUS seems to be spot on in the above observation. You can download this 3MB zipped file that contains yet-to-be final ASUS OC Guide and a quick white paper on PCB layout and memory clock signaling from our servers. This guide is NOT in its final form yet, but I doubt there will be any big changes made at this point. Actually, if you geek out on CPU and motherboards, it is actually a good read.

Haswell Tips and Tricks

There are a few things that you can do to possibly better your Haswell overclocking. The first thing to consider is simply a better cooling solution if you do not already have one. While the physical CPU socket has changed again, Intel has stayed smart and kept the cooler mounting hardware the same as it has been for a while now. LGA 1155, LGA 1156, and LGA 2011 spec coolers will work fine with LGA 1150. A huge Thermalright tower with 120mm push/pull fans or even better push/pull fans is going to likely be required to get enthusiast-grade stability in the 4.3GHz range. Beyond that, I think my first pick would be the Corsair H100i. Past those choices you are getting into spending some very serious money for cooling solutions like the Koolance Exos 2 we use for testing or even if you are DIYing the loop yourself.

I hope that I am being totally over-conservative on the cooling issue. Please keep in mind that I have only had the experience of using a single 4770K, but have had plenty of communication with ASUS, and ASUS has been extremely serious about getting a good motherboard launch with Haswell. I have never seen a company put so many reasons into the enthusiast side of a processor launch before. I tend to believe that ASUS exactly correct in what its people are communicating to me. Again, retail purchased Haswell processors and our readers sounding off in our Intel subforum will bore this out.

The second thing to consider is overclocking per core, if you motherboard supports that, which both the ASUS Z87-A and Z87-Deluxe do in both BIOS and desktop software. (The new AI Suite III software from ASUS is quite nice as well.) No, we did not show per-core OCing in this review, but it works. We do not show this because it adds more variables with trying to get repeatable benchmarks depending on how you are using the system. But, if you are simply wanting to get higher clocks out of your Haswell but are heat limited this should work for you. Start with core 1 and then scale the multiplier for each core down from there; 46, 45, 44, 43. This will allow you better performance in applications that are generally not CPU dependent or widely thread aware but benefit from high CPU clocks, like games.

Turning off HyperThreading on our i7-4770K helped us out with core temperatures in a big way. This is probably the single biggest thing you can do to cool off your Haswell 4770K. Turning off HyperThreading will knock a quick 5C to 8C off your individual core temperatures in our experience under high overclocks. Doing this hurts the performance of your processor, possibly a lot, possibly a little, depending on your application. To throw some quick numbers at you, when turning off HyperThreading on our 4770K running at 4.8GHz we saw: Cinebench scores decrease by over 20%, POV-Ray render times increase by 10%, Handbrake encode times increase over 7%, Lost Planet low resolution framerates decrease by 20%, and Metro Last Light low resolutions framerates decrease by 25%. Turning HyperThreading off in our high resolution / graphically intensive game benchmarks, we saw Lost Planet impacted less than 1%, and Metro: Last Light impacted less than 2.5%. So if you are using your 4770K with HyperThreading for workstation applications, a Torrent encode farm, or to play games on a 1024x768 CRT, then you will likely want to leave HyperThreading turned on. If you are using it for "modern" gaming, turning off HyperThreading to give you a better CPU overclock will likely benefit you more than losing CPU cycles with HT turned on.

Lastly, and a bit more on the [H]ard side of things, you can always get the razor blades out and pop the top on the thing. Folks that have successfully de-lidded their Ivy Bridge processors have seen temp drops across all cores of 5C or better, many times much much better. SonDa5 in our forums documented a 12C decrease, and took awesome pictures to show you the process. Obviously this comes with the risk of totally fubarring your CPU.


The Bottom Line

My experience for the last couple of weeks with Haswell has been a good time. It has been a lot of fun working with the new architecture and I had some really good feelings about it, but going back and truly analyzing the benchmark data, it left me feeling a bit flat. I skipped upgrading my personal system when Ivy Bridge launched and elected to stick with my Sandy Bridge at 4.5GHz which has been running happily for quite a while now. That was just a little more than 2 years ago. Obviously at identical clocks Haswell is a bit faster than Sandy Bridge, but given the way my personal system usage has changed in the last couple of years, does having 15% better encode times or zipping up a file folder 1 second faster really mean anything? I hardly ever rip and encode video files anymore in today’s digital download world and when I do, I am generally not in a huge hurry. And if I was, I would have a LGA 2011 Sandy Bridge-E system sitting at my feet. As we have repeatedly shown, if you are using applications that are heavily threaded and likely in the content creation arena, the more cores the better. That said, a Core i7-3930K will still cost you around $570, and the motherboards are still hovering around the $200 mark on the very low end of the spectrum.

From the hardware enthusiast perspective it is going to be very interesting to see what retail purchased processors give us clock-wise in the wild. With Sandy Bridge and to a lesser extent Ivy Bridge, you could pretty much go buy that 2600K or 3770K processor and know you are going to bang out a solid 4.6 or 4.7GHz without a terribly expensive cooling solution on a decently priced motherboard. With everything I am hearing now about Haswell, 4.6GHz is sounding kind of dicey without less than $100 invested in a cooling system. If you purchase a Haswell and overclock it and find out 4.4GHz is pushing it for your particular processor, well then your gains from Haswell's superior IPC will be lessening quickly.

From gaming enthusiast perspective quite simply your hard earned hardware dollar is better spent on a new video card or display. (Or SSD for that matter.) While certainly CPU clock speed comes into play in the gaming arena, the games we play are largely GPU limited and most of you reading this already likely know if you have "enough" CPU for gaming. Or you likely know you are few CPU generations behind and already know you will greatly benefit from a CPU and motherboard upgrade.

When I started out on this review project I did not think that Haswell would be a hard sell for the current Sandy Bridge owner, but that is exactly what I am thinking right now. I still might upgrade my personal SB system, but if I do, it will likely be because the ASUS motherboards I used over the last couple of weeks were actually what was getting me excited about Haswell rather than the processor.

I generally have a resolute opinion about hardware after I have spent this much time using it, but I think with Haswell I am going to have to see how the enthusiast hardware community embraces the retail i7-4770K and i5-4670K processors and the results those bear before I truly figure this one out. I think Intel has spoiled a lot of us overclockers in the last few years as it truly has been easy. Are we about to go back to the days of spotting the "Blue Core TBird?"

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