Well, This is Disappointing
The rumor mill has been working overtime on stories about Skylake’s performance. PCOnline showed over a 20% performance increase in Photoshop for example, yet we found the Core i7-6700K to be 5% slower. Other reports claimed up to 40% better integrated graphics performance over Broadwell and that certainly wasn't anything close to reality, at least when comparing the 6700K to the 5775C.
These claims could have been made regarding the mobile Skylake CPUs, so we will have to wait and see how that shakes out.
After our results indicated that the 6700K was no faster than the 4790K, we retested with the expectation of finding at least a 10% increase. However, it became clear that there was no extra performance and Intel’s own PR material only claimed "up to" a 10% increase, which means you can expect just a few percent for the most part.
Intel says you can look forward to as much as 10% more performance from the 6700K when testing with SPEC CPU2006. Unfortunately, we were unable to obtain a copy of this benchmark in time for the Skylake launch, but we did test with a wide range of applications and failed to find anywhere near a 10% gain.
The only results Intel provided that could be compared to our own were recorded using Cinebench R15 where Intel's in-house testing matched our own.
Since I can't confirm our numbers with Intel or get answers to any of the dozen questions I have regarding Skylake's performance and features, we just have to hope everything is in order.
For now it looks like the Core i7-6700K is at best able to match the 4790K. I can't put into words how surprisingly and ultimately disappointing that is.
Where Skylake does offer a few advantages over Haswell is in the new platform, more precisely the Z170 chipset which is superior to the Z97 chipset in several ways. The Z170 enjoys 40% more high speed I/O lanes (USB 3.0 and PCIe 3.0) over the Z97 chipset, while PCIe 3.0 storage support with Intel RST has also been added.
The key advantage of the Core i7-6700K over the 4790K is its improved efficiency and superior overclocking capabilities. Not only is the 6700K more flexible when it comes to overclocking but we found the results to be much more promising as well. Our sample had no trouble running at 4.8GHz on air which is 300MHz higher than our 4790K. We hope this is the norm.
Those coming from much older platforms will see some value in Skylake, at least the platform brings some new features and improved efficiency. Those already running Haswell gear will want to pass and the same can likely be said about Ivy Bridge users.
Those with a Sandy Bridge processor might be tempted, though we suspect 2500K owners will hold out for a more substantial upgrade. Just last week we revisited older Intel CPUs and found that some four-year-old Sandy Bridge models still had plenty of life left in them, not including their overclocking potential.
Pros: Skylake offers improved efficiency and overclocking over Haswell while the new Z170 chipset tops the Z97 with more USB 3.0/PCIe 3.0 lanes, PCIe 3.0 storage support and Intel RST.
Cons: The Core i7-6700K is generally no faster than the i7-4790K, which will make it difficult to coax purchases out Haswell and Ivy Bridge owners. Availability is rumored to be limited.