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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mapesdhs - Monday, July 24, 2017 - link
Let the memes collide, focus the memetic radiation, aim it at IBM and get them to jump into the x86 battle. :Ddgz - Monday, July 24, 2017 - link
Man, I could really use an edit button. my brain has shit itselfmapesdhs - Monday, July 24, 2017 - link
Have you ever posted a correction because of a typo, then realised there was a typo in the correction? At that point my head explodes. :DGlock24 - Monday, July 24, 2017 - link
"The second is for professionals that know that their code cannot take advantage of hyperthreading and are happy with the performance. Perhaps in light of a hyperthreading bug (which is severely limited to minor niche edge cases), Intel felt a non-HT version was required."This does not make any sense. All motherboards I've used since Hyper Threading exists (yes, all the way back to the P4) lets you disable HT. There is really no reason for the X299 i5 to exist.
Ian Cutress - Monday, July 24, 2017 - link
Even if the i5 was $90-$100 cheaper? Why offer i5s at all?yeeeeman - Monday, July 24, 2017 - link
First interesting point to extract from this review is that i7 2600K is still good enough for most gaming tasks. Another point that we can extract is that games are not optimized for more than 4 core so all AMD offerings are yet to show what they are capable of, since all of them have more than 4 cores / 8 threads.I think single threading argument absolute performance argument is plain air, because the differences in single thread performance between all top CPUs that you can currently buy is slim, very slim. Kaby Lake CPUs are best in this just because they are sold with high clocks out of the box, but this doesn't mean that if AMD tweaks its CPUs and pushes them to 5Ghz it won't get back the crown. Also, in a very short time there will be another uArch and another CPU that will have again better single threaded performance so it is a race without end and without reason.
What is more relevant is the multi-core race, which sooner or later will end up being used more and more by games and software in general. And when games will move to over 4 core usage then all these 4 cores / 8 threads overpriced "monsters" will become useless. That is why I am saying that AMD has some real gems on their hands with the Ryzen family. I bet you that the R7 1700 will be a much better/competent CPU in 3 years time compared to 7700K or whatever you are reviewing here. Dirt cheap, push it to 4Ghz and forget about it.
Icehawk - Monday, July 24, 2017 - link
They have been saying for years that we will use more cores. Here we are almost 20 years down the road and there are few non professional apps and almost no games that use more than 4 cores and the vast majority use just two. Yes, more cores help with running multiple apps & instances but if we are just looking at the performance of the focused app less cores and more MHz is still the winner. From all I have read the two issues are that not everything is parallelizable and that coding for more cores/threads is more difficult and neither of those are going away.mapesdhs - Monday, July 24, 2017 - link
Thing is, until now there hasn't been a mainstream-affordable solution. It's true that parallel coding requires greater skill, but that being the case then the edu system should be teaching those skills. Instead the time is wasted on gender studies nonsense. Intel could have kick started this whole thing years ago by releasing the 3930K for what it actually was, an 8-core CPU (it has 2 cores disabled), but they didn't have to because back then AMD couldn't even compete with mid-range SB 2500K (hence why they never bothered with a 6-core for mainstream chipsets). One could argue the lack of market sw evolvement to exploit more cores is Intel's fault, they could have helped promote it a long time ago.cocochanel - Tuesday, July 25, 2017 - link
+1!!!twtech - Monday, July 24, 2017 - link
What can these chips do with a nice watercooling setup, and a goal of 24x7 stability? Maybe 4.7? 4.8?These seem like pretty moderate OCs overall, but I guess we were a bit spoiled by Sandy Bridge, etc., where a 1GHz overclock wasn't out of the question.