I voluntarily cut the memory bandwidth in my production PC in half.
My recently replaced production system consisted of a Core-i7-5930K Haswell Extreme processor and 32GB of DDR4 DRAM running at 2133MHz effective, installed onto a Gigabyte X99-UD5-WiFi motherboard.
That translates to a peak memory bandwidth of 68GB per second. The processor clocked at a stock 3.5GHz (3.70GHz turbo boost), with a TDP of 140W — a hefty power draw by today’s standards. The system also include an Nvidia GTX Titan graphics card, a Samsung EVO 840 2TB SSD, and a Sound Blaster ZXR sound card, all housed inside a Corsair Obsidian 550D case. The system performed pretty well, though it was a little noisier than I would expect, given the Seasonic 750W power supply and Corsair sealed liquid cooler.
I decided I wanted to cut power consumption a bit, reduce noise, and update the platform. That last element is the key one: I wanted to maintain good performance, but move to USB 3.1. When Intel finally began delivering Core i7-6700K processors built on their new Skylake CPU architecture, I switched over. The Core i7-6700K runs at a base clock frequency of 4GHz, and can turbo-boost to 4.2GHz. Although it runs at a higher clock frequency than the 5930K, the 6700K also contains fewer CPU cores — four, as opposed to the six cores in the i7-5930K. The cache is also smaller, at 8MB versus 15MB. Then again, rated power is 91W. Overall power consumption seems down. Of course, I needed to replace the motherboard as well, so opted for another Gigabyte board, the Z170X-Gaming 7.
The system is substantially quieter than the Haswell Extreme incarnation. None of the cooling fans — CPU, power supply, or graphics card — kick in under normal desktop use. I can have several dozen chrome tabs open, be editing a Word document, and have music playing, and the PC itself is dead quiet. It’s only when I fire up a game that I hear the cooling fans kick in. Based on that factor alone, I consider the changeover a success.
What about performance? I haven’t run benchmarks, but subjectively, I’ve noticed no differences when running office apps, editing photos in Photoshop, or when playing games. Bear in mind that the other components in the system remain the same, including the graphics card, SSD, and 32GB of DDR4. If I were running bandwidth intensive applications, such as serious video editing, or applications where the additional cores would have been useful, such as building code, I may have noticed a difference. As it stands now, however, I feel like I’ve given up nothing to go to a lower power, more modern platform.
