One of my favorite past exercises in building my own computers was creating a spreadsheet listing all the components and prices. I’d start with the motherboard, case and power supply. I’d then fill in RAM, GPU, optical and storage drives until I’d selected everything except the CPU. Like many DIYers, I loved researching which chips could be purchased at a low price, but handle an aggressive overclock. There was an excitement in finding a $150 overclockable CPU that gave $300 models a run for their money.
That was the case with the legendary AMD Athlon XP-M 2500+. AMD made a desktop equivalent model with a locked down multiplier, but once gamers realized how much potential was in the unlocked mobile version, they began pushing it into the 2.5 GHz range, a substantial boost from its 1.83 GHz stock clock speed. Intel also released a few inexpensive chips with excellent overclocking features. The Intel Pentium D 820 and 805 come to mind because they undercut the pricing of AMD’s Athlon 64 X2 line of processors by about $100. The crew over at Tom’s Hardware was able to overclock a $130 dual core Pentium D 805 to 4.1 GHz. The chip’s stock clock speed came in at a modest 2.66 GHz, but could be pushed over 4 GHz with few changes to cooling. As you can imagine, gamers and enthusiasts couldn’t snatch them up fast enough.
Few CPUs captured the attention of overclockers like the Pentium D 805
The overclocking glory days took place about 10-12 years ago. Since then AMD has conceded the high-end of the desktop CPU market to Intel, and clock speeds have taken a backseat to physical CPU core counts. Sure, Intel has released a number of processors aimed at overclockers such as the Core 2 Quad Q6600 and Core i7-920. But today’s processors are primarily about physical core counts that utilize technology to push clock speeds higher when needed, but otherwise conserve power when not under load.
Rekindled Interest in Overclocking
Desktop processors have settled in around the 2.7 to 4.0 GHz range. Two of the most popular processors from Intel come from their Skylake line: i5 6600K (3.5 GHz) and i7 6700K (4.0 GHz). If you were to purchase a mid to high-end computer today for tasks ranging from content creation to gaming, you’re probably considering one of these CPUs. Both of these processors include a feature from Intel called Turbo Boost that’s quite sophisticated. At its most basic level, it allows the CPU to monitor the workload and increase the clock speed when performing intensive, single threaded tasks. There are many factors involved in determining the increased clock speed, but the performance gain can be substantial. Both the i5 6600K and the i7 6700K will Turbo Boost to 3.9 GHz and 4.2 GHz respectively. That’s basically a free performance gain without having to make any changes to your BIOS, and for most people, this is enough. Imagine your car engaging a couple extra cylinders when passing on the freeway or climbing hills. That’s basically what Turbo Boost does to your CPU.
But there are enthusiasts who love a challenge and haven’t been thrilled with the continual move to more cores which boost the ability to run several tasks in parallel while sacrificing clock speed. They tweak and they push and they probably torch a few CPUs on their quests to eek out every ounce of chip performance. They aren’t satisfied with Turbo Boost and blame Intel for diminishing overclocking capabilities of their products. But does it still make sense to overclock desktop CPUs? What about those in workstations and servers? Looks take a closer look.
Desktop CPU Overclocking
This is where most overclocking is done because this covers the gamers who are the most likely to overclock their CPU and GPU. But general office usage also falls under this category, and even the most basic i3 or i5 CPU will perform office tasks admirably. While the current Intel chip architecture, Skylake, handles a modest overclock, that hasn’t been the case with each new architecture. Haswell and Ivy Bridge models didn’t lend themselves to more than a very mild overclock.
Does it make sense to overclock your basic office desktop CPU? Not really. We’ll talk about the tradeoffs later, but it’s generally not worth the hassle. If you think overclocking an i3 will save you money, you should consider an i5 instead. Overclocking will always introduce more heat and that means any money you save on the CPU will be put put towards a 3rd party cooler because the stock cooler won’t be enough to handle the excess heat. In fact, I don’t recommend using air to cool an overclocked CPU. You can go full-liquid cooling but that adds more complexity and expense. There are other options such as the Corsair Hydro H60 that’s self-contained and require no maintenance. It does a great job of cooling hot-running processors while not costing much more than a quality air-cooled solution.
The Corsair Hydro H60 is a self-contained CPU cooler aimed at overclocked systems
Gamers might find scenarios where overclocking a Skylake CPU is worthwhile, but it really depends on the games you play. And honestly, you’re better off purchasing a moderately priced CPU and putting the extra savings into a higher-end GPU because the bottleneck in most games is the GPU. Even if you do decide to overclock your CPU, expect a modest increase in FPS.
Workstation & Server Overclocking
While desktop users might have patience when dealing with computer issues, workstation and server admins generally want the most reliable and stable system they can build because they are losing money when those workhorses go down. So it’s very difficult to recommend overclocking when reliability and stability are paramount to your workflow.
With this in mind, I’ve been surprised to field questions from professionals running programs from AutoCAD to Photoshop to SolidWorks about whether overclocking would improve the performance of these and other programs. From the testing we’ve done at Puget Systems, there are no easy answers to this question because the software and features used vary from user to user. We recently decided to see if it made any sense to overclock the CPU when running Solidworks. Solidworks is a solid modeling CAD and CAE program that runs on Windows and is used by over 2 million engineers. Based on our testing, we found only modest gains in performance on a handful of tasks. Server tasks such as server web pages or hosting VMs benefit from more cores and lot of memory, so there’s no need to overclock in those scenarios.
While most desktops run Intel Core Series processors that include the i3, i5 and i7 lines operating at various clock frequencies, most workstations and servers use Intel Xeon processors that don’t lend themselves to overclocking. This makes sense because workstations and servers are built to handle many tasks simultaneously which is best handled by processors with many physical cores rather than one with fewer cores at higher clock speeds. Xeon processors are built for environments where reliability is king so you have an ecosystem built around Xeon processors that include ECC-REG memory, server-grade motherboards, ultra-reliable SSDs and support for the most stable operating systems. Overclocking a workstation might sound reasonable on paper, but the tradeoffs usually go against the reason for building a workstation in the first place.
Overclocking has been around for a while, but the risks associated with the practice remain unchanged. The process of overclocking involves tweaking settings in the BIOS and a lot of testing. You may have to adjust the CPU multiplier, bus speed, and various voltages in order to find the right balance between speed and stability. Under ideal circumstances, you’ll be tweaking and testing and then testing some more. At worst? You could fry your CPU, motherboard and RAM. You really shouldn’t attempt this unless you have someone who is experienced and understands the risk involved. Other risks include:
*Excess Heat/Fan noise
You’ll have to be the judge whether the risk outweigh the increases in performance. If you have an older Pentium or Sandy Bridge CPU collecting dust, you might see if you can push them to the edge without going over. But I advise against purchasing a lower-end CPU with hopes of overclocking it into the performance realm your workflow demands. We used to live in a world where each new version of Windows required significant hardware upgrades in order to operate properly. But that’s just not the case today where Sandy Bridge CPUs from three or four years ago handle Windows 10 without any issues.
Do you plan to overclock your CPU or are the risks just not worth it?