Bug In Intel H87 Chipset Allows Ratio-Based Overclocking

Intel thought it was helping out enthusiasts by giving Haswell-based K-series SKUs access to a handful of BCLK straps. Instead, the hotter-running, voltage regulator-integrating parts tend to underperform Ivy Bridge-based air-cooled CPUs when it comes to overclocking headroom. As a result, we really didn’t see any reason to upgrade in The Core i7-4770K Review: Haswell Is Faster; Desktop Enthusiasts Yawn, particularly since you’re forced to buy a new motherboard as well.

Previously, you needed a Z-family platform for access to overclocking functionality. That was supposed to carry over to Intel’s Lynx Point chipsets. However, we noticed a BIOS option called “Non-Z OC” in ASRock’s H87 Performance motherboard that suggested Intel might have forgotten to turn unlocked ratios off in one of its lower-end platforms.

It turns out that you can drop a K-series CPU into the well-equipped $105 motherboard and overclock it using the processor’s ratio multipliers. The cost savings compared to Z87 is almost large enough to make up for the fact that Intel charges an extra $40 for its -4770K over the locked-up -4770.

Non-Z OC Options

We still think the Haswell-based flagship is priced poorly at $350 when you can get a Core i7-3770K for $320. However, it’s also pretty funny that, despite Intel’s attempts to charge enthusiasts extra for their hobby, the company seems to have left the back door wide open on its less expensive H87 Express platform controller hub.

All Cores at 4.8 GHz

It’ll be interesting to see if other motherboard vendors come out with enthusiast-oriented boards centering on H87 Express to capitalize. Although H87 still prevents you from splitting the processor’s PCI Express connectivity into multiple links, powerful single-GPU cards like Nvidia’s GeForce GTX 770 and AMD’s Radeon HD 7970 still make it possible to build an affordable gaming machine using the lower-end platform.

We're also trying to confirm whether this works using Core i5-4670K, which is a lot more affordable at $240. That could end up being a value favorite you see show up in next quarter's System Builder Marathon.

Chris Angelini
Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.
  • KnowItAll
    Is there ever NOT some kind of bug in a new Intel chipset?
  • WithoutWeakness
    "Non-Z OC" definitely sounds like ASRock knew this was an option when they built their BIOS/UEFI for this board. I wonder if Intel knew about this bug and if ASRock could get in some trouble for implementing this. Regardless, this is a huge value-add for a lower end board and, as the article states, could make this board the best bang-for-the-buck for single-card gamers who want to tinker with overclocking.
  • hixbot
    Wow the price difference between "Z" and "H" ITX mobos is even greater. This could be a big savings for SFF overclocks.
  • Estix
    11044454 said:
    Is there ever NOT some kind of bug in a new Intel chipset?

    It's not a bug, it's a feature!
  • de5_Roy
    this could end up being a great news for budget overclockers....
    intel forces motherboard vendors to release a bios/uefi patch to lock down non-z o.c. intel hates o.c.ers.

    could you guys test non-k core i5 cpus along with the core i5 4670k? i know intel locked out non-k cpus off bclk o.c. but they also locked out h87 off bclk o.c. :)
  • Wisecracker
    Unintentionally on purpose, perhaps ?

  • CaedenV
    Does this mean we can figure out the bug and apply it to an older non-Z chipset to make Sandy and Ivy chips in slower boards run faster?
  • audiophillia
    haha. I just bought that exact motherboard. notice OC features in the bios and asked about it on the forums. everyone assured me I could not OC on my h87 performance board.
  • Grandmastersexsay
    The price difference between an H87 and Z87 amount to about 1% of the budget for a low end performance build.

    You guys also sound like idiots recommending a 3770K over a 4770K juat to save $30. The haswell chip will give you anywhere between 5% to 10% better perfornance. Who cares if it overclocks an extra 100 Mhz for a given temperature.
  • sundragon
    Bug or intentional? :)

    I wonder how long before they release a bios update that closes it.