Hexa-core honey you can almost afford
Is bifurcation necessarily bad? That sounds like a soporific keynote speech for a dreary business conference. But it's actually been a critical question for performance PC lovers ever since Intel split its desktop processors into two distinct platforms way back in 2008.
Specifically, it means Intel has been running two mutually incompatible processor sockets, one for high-end desktop PCs, another for everything else. On the upside, creating a true high-end platform means Intel can inject features that just wouldn't be feasible in cost terms if present in every PC. On the other, it creates an impenetrable barrier in the upgrade path. No longer could you drop in every Intel CPU from poverty spec to bleeding edge into a single socket. Now you’d need at least a new CPU, new motherboard and likely new system memory, too. Ouch.
What's more, for much of the time, the performance jump from the best of Intel’s mainstream chips to the bottom rung of its high-end platform hasn't been spectacular, despite coming at a painful price. What’s more, a closer look at Intel’s high-end platform has always left the uneasy impression of being thinly disguised server hardware complete with features that are fairly redundant for the desktop.
That’s the conflicted context for the i7-5820K. It’s compatible only with Intel’s high-end platform, which today means the LGA2011v3 socket and the X99 chipset. With its quad-channel DDR4 memory subsystem, the sense of server-system bandwidth overkill remains. But the 5820K might just be the most appealing chip yet for one of Intel’s modern high-end platforms.
Partly, that comes down to pricing. At over £300, it's not exactly cheap. But it's not that much more expensive than the top chip for the LGA1150 socket, namely the i7-4790K. Okay, you have to factor things like motherboard and memory into the equation. But odds are, whatever CPU you buy, you'll need a new motherboard to go with it. So, you might be able to restrict the overall price premium of going with Intel's high-end platform to under £100.
Interesting, but what does it buy you? In the case of the 5820K, the most obvious upside is an extra pair of CPU cores and thus six cores in total. What’s more, thanks to the delay in bringing the Broadwell CPU family to market, both chips sport Haswell-style CPU cores, where previously Intel's high-end platform has tended to run a generation behind.
Of course, the 4790K’s cores are clocked higher at 4GHz nominal and 4.4GHz Turbo, versus 3.3GHz and 3.6GHz for the 5820K. But both chips are fully unlocked. In our overclocking tests, the 4790K tops out at 4.7GHz with the 5820K only a little behind at 4.45GHz. That 250MHz difference represents roughly a five per cent frequency disadvantage, hardly a huge penalty to pay for 50 per cent more cores.
Even running at standard clocks, the 5820K inevitably hammers its quad-core sibling in heavily multi-threaded software like image rendering and video encoding. Factor in overclocking and it s no contest.
You might expect good old games to turn the tables. Indeed the 4690K is generally a bit quicker in games. But the advantage is is hardly dramatic. Moreover, if it's a pure gaming CPU you seek, it's actually the 4690K and its simpler quad-core design and lack of Hyper-threading support that makes for the uncomfortable comparison and the better bet, not the 4790K.
However, as an all-rounder, the 5820K is seriously appealing. That's especially true when you factor in its advantage in terms of extra PCI Express lane availability over any Intel CPU sitting in the LGA1150 socket. As SSDs move to PCIe interfaces, it could make the difference between running everything at full speed and having to make some tricky compromises.
Six of Intel’s finest CPU cores; epic multi-threading performance; best platform features in the business.
SPECIFICATIONS
CPU cores/threads 6/12
Process technology 22nm
Clockspeed 3.3GHz, 3.6GHz Turbo
CPU architecture Haswell-E
Socket LGA2011v3