Intel takes the iGPU lead, for a price
B roadwell has been a long time coming to the desktop, but it’s finally here in the form of Intel’s i7-5775C. It’s the codename for Intel’s move to a 14nm manufacturing process, known as a tick in Intel’s tick/tock cadence, and has been long overdue thanks to production issues. While laptops have benefited from Broadwell’s powersipping process since late 2014, it’s only now that desktop users get to see what all the fuss is about. And while the move to 14nm is impressive, it’s the beefed up Iris Pro graphics in this processor that steals the show.
First, the basic specs. This is a quadcore, HyperThreaded CPU, with a base frequency of 3.3GHz and Turbo Boost speed of 3.7GHz, and 6MB of L3 cache. The TDP of just 65W shows just how cool the new 14nm process is. The older i5-4690K, which runs at similar speeds, has a TDP of 84W, and yet it doesn’t have anywhere near as much silicon devoted to the integrated GPU. It supports DDR3 memory up to speeds of 1600MHz, though motherboard makers can get around this easily enough. It can serve up to 16 lanes of PCI Express 3.0, while it’s still using the Socket 1150 design of the last generation. Don’t expect to just slap it in any old Socket 1150 motherboard though; when we installed it in our Asus Maximus VII Hero, games would crash and the system would spontaneously lock up. It turned out that a BIOS update is necessary for most motherboards to support this new chip. Despite the lack of a K in the name, this CPU is multiplier unlocked, making overclocking a breeze.
Where it gets really interesting though is the inclusion of Intel’s Iris Pro Graphics 6200. As you can see from the die map, approximately half of the silicon in this CPU is dedicated to the graphics processor, a huge step up from prior Intel iGPUs. Compared to prior versions of Iris Pro, such as the 5200 used exclusively in Apple’s Macbook Pro and iMac, the number of execution units has increased from 40 to 48. It’s an even bigger leap from the HD Graphics 4600 commonly found in Intel-powered laptops, which only had 20 execution units. The GPU has a maximum frequency of 1150MHz, which is slightly down on the 1250MHz of HD Graphics 4600, likely due to the increased complexity of the iGPU. A whopping 128MB of eDRAM serves as an L4 cache, and this can be accessed by the iGPU to help mitigate the slow speed encountered when accessing the system’s memory.
AMD has held the integrated graphics crown for several years now thanks to the powerful GCN cores in its APU range, but Iris Pro Graphics 6200 promises to change all that. To test its performance we first fired up Grid AutoSport, at a resolution of 1920 x 1080 with the preset graphics options set to medium. No dedicated graphics card was installed in the test system, with all graphics being piped directly from each motherboard’s HDMI output. The Intel i7 5775C had a handy 10% performance lead over AMD’s new A10 7870K, with an average framerate of 54fps. Next off the benchmarking rack was the demanding Shadow of Mordor, and due to its high performance hunger we lowered the resolution to 1280 x 720, with low graphics details. Once again Intel posted the win, this time by 18%, leaving us in no doubt as to which is the better CPU for gaming overall.
Our final benchmark was the systemwide PCMark 8 Home, where Intel’s superior raw CPU performance saw it beat the AMD chip by a whopping 38%. However, it’s worth pointing out that the Intel chip is twice the price of AMD’s new processor; while Intel might have taken the iGPU performance throne, it cost them a pretty penny to do so. There’s also the fact that this CPU is so late that Intel’s next CPU, Skylake, looks set to make it obsolete in the next month or two. As a result, we’d highly recommend holding o¡ on your next CPU upgrade until we see what Skylake can deliver. Bennett Ring
KEY SPECS
Quad-Core • HyperThreading • 3.3GHz base frequency, 3.7GHz Turbo Boost frequency • Socket 1150