Intel's devilish quad-core all-rounder
Normally, buying the most expensive version of any CPU is for chumps. It means having your wallet hammered in return for a spec bump that's more about scoring a PR win than actually improving your end-user experience. Should you therefore be doubly wary of the Intel Core i7-4790K? After all, it’s just the top chip for Intel's LGA1150 socket. It’s a stopgap replacement for what was once the range-topping quad-core Intel Haswell CPU, the 4770K.
In fact, very likely the only reason the 4790K even exists is because the Unm Broadwell CPU architecture is running late in desktop format and Intel wheeled it out for the sake of simply having something new to sell. Is the 4790K therefore the ultimate PR processor?
That’s not entirely fair. The 4790K isn't simply the same old Haswell quad-core chip taken from a better speed bin and running at slightly higher clocks. There's more to the 4790K, and its so-called Devil's Canyon sibling the 4690K, than that.
The big news is an upgraded thermal interface material, or TIM for short. The TIM is a thermal material that connects the CPU silicon itself with the metal heat spreader that forms the top of the CPU package and interfaces with whatever cooler you are using. Arguably, the 4790K only benefits from an improved TIM because Intel had cheaped out on the TIM for mainstream Haswell processor models. What’s more, some say that it’s actually increased spacing between the silicon and heat spreader, not the TIM material, that’s been the problem with Intel CPUs of late.
Whatever, for the two Devil’s Canyon chips, Intel upgraded the TIM and in turn bumped up the clockspeeds pretty dramatically. Where the older 4770K was clocked nominally at 3.5GHz and 3.9GHz Turbo, the 4790K rocks in at 4GHz and 4.4GHz respectively. By any metric, 500MHz is a healthy boost.
The consequence is a quad-core, eight-thread CPU that looks pretty zippy in almost any test. At stock clockspeeds, it's enough to make you wonder whether you really need that six-core 5820K CPU. After all, is the broader investment required for the upscale LGA2011v3 platform worth it to increase your video encoding grunt from 53 frames per second to 62?
What's more, at these clocks and with the Haswell architecture, single-threaded performance is simply monster. In fact, this Intel chip is about twice as fast in the Cinebench single-threaded test as the AMD processors in the lab this month. Not that they’re directly competitive CPUs. But it does give you a flavour of the task AMD faces with its new Zen CPU architecture next year. AMD could take a big step forwards and still be a fairway behind Intel.
Still, if there's a disappointment with the 4790K, it involves overclocking. The difficult thing with overclocking, of course, is that it varies from chip to chip. You can't simply apply sweeping generalisations. For the record, our test chip tops out at 4.7GHz. But based on the 4790K chips we've seen ourselves, along with reports around the web, that seems fairly typical.
That's both a little disappointing in absolute terms, versus the standard factory clockspeeds, and not dramatically better than the 4.6GHz we’re used to seeing from the old A770K. So much for that upgraded TIM, then.
However, our main objection remains pricing, which if anything has crept up in retail reality recently. The top end of Intel’s mainstream platform has always felt expensive. At over £250, the 4790K is no exception. As things stand right now, its appeal as a primarily gaming CPU compared to the A690K is marginal at best.
If gaming is what you’re all about, forget about the 4790K. If you’ve a broader remit, the 4790K makes more sense. But we'd suggest you spend a bit more and step up to the LGA2011v3 platform and the 5820K.
Awesome at almost everything; even quicker when overclocked; improved thermal management.
SPECIFICATIONS
CPU cores/threads 4/8
Process technology 22nm
Clockspeed 4GHz, 4.4GHz Turbo
CPU architecture Haswell
Socket LGA1150