- Wednesday, August 05, 2015
- Kyle Bennett
Intel Skylake Core i7-6700K IPC & Overclocking Review
Today we finally get to share with you our Intel Skylake experiences. As we like to, we are going to focus on Instructions Per Clock / IPC and overclocking this new CPU architecture. We hope to give our readers a definitive answer to whether or not it is time to make the jump to a new desktop PC platform.
Please keep in mind as you go through our data that all our CPUs and RAM in our top group are clocked identically. 4.5GHz CPU clock and 1866MHz memory clock. Memory timings are spelled out on our test system page, and I would give those a look because as we scale our memory clocks, our timing lantencies do in fact increase greatly and you will see this impact some of our testing. In the group of data in the middle we show Skylake performance while scaling memory from 2133MHz to 3600MHz while keeping the CPU clock at 4.5GHz. Finally in the bottom line of data we show Skylake overclocked to 4.8GHz with 3600MHz memory.
Also it is very worthy of pointing out that 2133MHz is the "stock" or "default" memory clock on a Skylake / Z170 chipset platform. We are showing retarded 1866MHz DDR4 speeds in order to have an "apples to apples" comparison to our previous DDR3 platforms and we were simply curious about this and we think that having it in our charts paints a truer picture of the Skylake processors.
It is highly unlikely that anyone will be using DDR4 at these lower speeds. According to PC Hound, as of writing this the most popularly purchased DDR4 memory kit is rated at 2400MHz. The two most popularly purchased memory kits behind that are rated at 3000MHz.
As always, these benchmarks in no way represent real-world gameplay. These are all run at very low resolutions to try our best to remove the video card as a bottleneck. I will not hesitate to say that anyone spouting these types of framerate measurements as a true gameplay measuring tool in today’s climate is not servicing your needs or telling you the real truth.
The gaming tests below have been put together to focus on the processor power exhibited by each system. All the tests below consist of custom time demos built with stressing the CPU in mind. So much specialized coding comes into the programming now days we suggest that looking at gaming performance by using real-world gameplay is the only sure way to know what you are going to get with a specific game. Our CPUs & Real-World Gameplay Scaling would be a great place to start.
Yes, this original Lost Planet benchmark is very long in the tooth, but it still remains one of the few game engines that tremendously benefits from multicore processor usage.
Our Skylake does not look too good here compared to our Haswell (1% increase). 9% faster than Ivy Bridge. 13% faster than Sandy Bridge. When we take our Skylake up to its stock 2133MHz speed we see an increase of 5% over Haswell, 13% over Ivy Bridge, and 17% over Sandy Bridge. 2666MHz memory gives us a 10% increase over Haswell.
Converse to what we saw on our previous pages, we see memory bandwidth scaling greatly impact our scoring, or frames per second in our games.
This is our first instance of seeing Skylake being slower than Haswell in our "apples to apples" testing. That is quickly remedied by scaling Skylake's memory bandwidth however. That all said, Heaven is our most GPU specific benchmark being used here so I would expect our scaling to be more compact. Still it shows that memory bandwidth can impact gaming engines.
I debated even showing this benchmark, because I am not sure that something "buggy" isn't going on with this older gaming engine. But again, even those we see Skylake come in a bit slower than Haswell (8%), we do see that memory bandwidth in this gaming engine is very important.
And lastly, Metro: Last Light is certainly one of our newest and most popular gaming engines used. This one is also run at a higher resolution with higher image quality, so it should be more GPU limited than the others. Our "apples to apples" results show Skylake with a 3% increase over Haswell, a 9% increase over Ivy Bridge, and a 12% increase over Sandy Bridge. Again we see that bringing Skylake up to its stock 2133MHz memory clock will give it a solid boost, and scaling up to 2666MHz and above will bring large increases.