Friday, February 3, 2017

No, the i3-7350K is not almost a i7-2600K

AnandTech ran an article today "The Intel Core i3-7350K (60W) Review: Almost a Core i7-2600K" that asks when Intel's newest budget overclocking CPU (the dual core i3) would match the venerable Sandybridge mainstream flagship (2600K).
If we’re only speaking performance (I’m sure Intel would rather happily speak efficiency), judging by our benchmark results, we’re almost there already. 
But there were two severe problems that make render his 14 page article largely useless. The first is that most of the people who pay the premium for overclocking CPUs are going to overclock them. Stock clock results are good data to have but largely reflect Intel's artificial product differentiation strategy.* The second is that many of the gaming benchmarks chosen weren't even CPU limited. Those are illustrative of the fact that most games are GPU limited but there are many games out there that are CPU limited in different ways, e.g., some favor more cores (The Division), some favor higher frequencies (ArmA/DayZ), some do better with more cache, various combinations of these, etc. But even in these games, a reviewer really should include overclocked results. What makes it worse is that Ian Cutress took the time to bench IGP results.


A lack of overclocked results make AnandTech's comparison poorly done. The problem is akin to that which plagues Amazon Vine reviews, namely, that the reviewer is approaching a product as a product to review rather than a product to solve a problem. It's frustrating because AnandTech used to be a premier review site.

An example of a competent comparison was done by Richard Leadbetter in in his article "Is it finally time to upgrade your Core i5 2500K?" which not only compares overclocked CPUs but also the effect of higher memory speeds possible with newer platforms. Frame time graphs and a wider program suite would be welcome, but Leadbetter's analysis is far more useful.


Is the i3-7350K almost an i7-2600K? It has better single threaded performance thanks to superior IPC and frequencies (both stock and OC) than the 2600K. For most applications, that's what matters. In multithreaded applications of multitasking, it's not as clear cut.

If the choice were between a 2-core 10GHz part and a 4 core 5GHz part where "aggregate" performance is equal, the higher frequency part is absolutely superior. But in cases where you can gain 100% more cores with a roughly 20% penalty in single threaded performance as is the case with the old i7 versus the new i3 , the picture isn't as clear. It all depends on the workload you have.

In general, though, the type of user who bought the 2600K back when fewer applications were optimized for multithreading will suffer a large downgrade, not a sidegrade as Ian Cutress suggests, by going to a 7350K.

* Since the advent of Sandybridge in 2011, Intel CPUs have largely settled on an overclock a bit higher than 4.5GHz – TIM issues aside. Intel's default clocks were much more conservative until recently which matters if you had a non-K processor but doesn't matter when looking at K processors, e.g., AnandTech's article.

  • 2600K 3.5GHz base 3.7GHz boost
  • 3770K 3.5GHz base 3.7GHz boost
  • 4770K 3.5GHz base 3.7GHz boost
  • 4790K 4.0GHz base 4.4GHz boost
  • 6700K 4.0GHz base 4.2GHz boost
  • 7700K 4.2GHz base 4.5GHz boost

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