The Intel Kaby Lake-X i7 7740X and i5 7640X Review: The New Single-Threaded Champion, OC to 5GHz
by Ian Cutress on July 24, 2017 8:30 AM EST- Posted in
- CPUs
- Intel
- Kaby Lake
- X299
- Basin Falls
- Kaby Lake-X
- i7-7740X
- i5-7640X
Benchmarking Performance: CPU Rendering Tests
Rendering tests are a long-time favorite of reviewers and benchmarkers, as the code used by rendering packages is usually highly optimized to squeeze every little bit of performance out. Sometimes rendering programs end up being heavily memory dependent as well - when you have that many threads flying about with a ton of data, having low latency memory can be key to everything. Here we take a few of the usual rendering packages under Windows 10, as well as a few new interesting benchmarks.
All of our benchmark results can also be found in our benchmark engine, Bench.
Corona 1.3: link
Corona is a standalone package designed to assist software like 3ds Max and Maya with photorealism via ray tracing. It's simple - shoot rays, get pixels. OK, it's more complicated than that, but the benchmark renders a fixed scene six times and offers results in terms of time and rays per second. The official benchmark tables list user submitted results in terms of time, however I feel rays per second is a better metric (in general, scores where higher is better seem to be easier to explain anyway). Corona likes to pile on the threads, so the results end up being very staggered based on thread count.
More threads win the day, although the Core i7 does knock at the door of the Ryzen 5 (presumably with $110 in hand as well). It is worth noting that the Core i5-7640X and the older Core i7-2600K are on equal terms.
Blender 2.78: link
For a render that has been around for what seems like ages, Blender is still a highly popular tool. We managed to wrap up a standard workload into the February 5 nightly build of Blender and measure the time it takes to render the first frame of the scene. Being one of the bigger open source tools out there, it means both AMD and Intel work actively to help improve the codebase, for better or for worse on their own/each other's microarchitecture.
Similar to Corona, more threads means a faster time.
LuxMark v3.1: Link
As a synthetic, LuxMark might come across as somewhat arbitrary as a renderer, given that it's mainly used to test GPUs, but it does offer both an OpenCL and a standard C++ mode. In this instance, aside from seeing the comparison in each coding mode for cores and IPC, we also get to see the difference in performance moving from a C++ based code-stack to an OpenCL one with a CPU as the main host.
Luxmark is more thread and cache dependent, and so the Core i7 nips at the heels of the AMD parts with double the threads. The Core i5 sits behind the the Ryzen 5 parts though, due to the 1:3 thread difference.
POV-Ray 3.7.1b4: link
Another regular benchmark in most suites, POV-Ray is another ray-tracer but has been around for many years. It just so happens that during the run up to AMD's Ryzen launch, the code base started to get active again with developers making changes to the code and pushing out updates. Our version and benchmarking started just before that was happening, but given time we will see where the POV-Ray code ends up and adjust in due course.
Mirror Mirror on the wall...
Cinebench R15: link
The latest version of CineBench has also become one of those 'used everywhere' benchmarks, particularly as an indicator of single thread performance. High IPC and high frequency gives performance in ST, whereas having good scaling and many cores is where the MT test wins out.
CineBench gives us singlethreaded numbers, and it is clear who rules the roost, almost scoring 200. The Core i7-2600K, due to its lack of instruction support, sits in the corner.
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MrSpadge - Monday, July 24, 2017 - link
> realize that overclocking may not be appropriate for these workloadsThat's going too far. Just don't overclock as far for heavy AVX usage.
MrSpadge - Monday, July 24, 2017 - link
Kind of agreed. Ian, you should log the clock speeds during benchmark runs and check for anomalies. The chip or mainboard could throttle, or your 4.0 GHz AVX clock could just be way too low. What's the default AVX clock? Maybe 4.4 GHz? That would pretty much match the 10% performance degradation.Ian Cutress - Monday, July 24, 2017 - link
I need to do a performance scaling piece, I know. It's on the to-do listKvaern1 - Monday, July 24, 2017 - link
As already mentioned it's heavy AVX workloads which makes it throttle when OC'ed. The same thing happens on OC'ed Skylakes.arh2o - Monday, July 24, 2017 - link
Something seems wrong with the 7700k results vs the 7600k results. How is the 7600k beating the 7700k so handily in all the games? Are you sure the graphs are not swapped? ROTR shows the 7600k beating the 7700k by 20 FPS which seems impossible considering most reviews on this game have the 7700k on top of the 7600k.ydeer - Monday, July 24, 2017 - link
I would have liked to see some idle power consumption numbers because my PC is always on.Ro_Ja - Monday, July 24, 2017 - link
This was an interesting read. Thank you!Marnox - Monday, July 24, 2017 - link
According to Intel (https://ark.intel.com/products/97129/Intel-Core-i7... the Turbo speed for the 7700K is the same as the 7740X.mapesdhs - Monday, July 24, 2017 - link
Is the Max Turbo for one core or two? Always bugged me that Intel doesn't list the individual core/bin levels.versesuvius - Monday, July 24, 2017 - link
It will be interesting to see how many of these CPUs Intel will actually produce (collect ?) and bring to the market.