I'm looking at buying a new laptop PC (my old one is failing). I noticed the latest CPU clock speeds are lower than my current one though the CPUs are newer. It used to be that a higher clock speed meant better performance but obviously this is no longer true.

So when I compare CPUs, how do I know what's good or bad? See below a screenshot of 3 CPUs. The one with the worst score is my current CPU.

Thanks, David.

  • Intel Core i7-4510U @ 2.00GHz
  • Intel Core i7-2620M @ 2.70GHz
  • Intel Core i7-4600U @ 2.10GHz

PassMark - CPU Performance Comparison

  • 1
    Why are you trying to compare a Sandybridge part to a Haswell parts? You cannot compare them, alright you can, but it doesn't make sense to since they would require entirely different hardware. The 4600U is a Haswell and 4510U is a haswell refresh part. – Ramhound Sep 30 '14 at 16:33
  • You're kind of making my point: I don't know enough about these differences / architecture to make a judgement. – David Brossard Sep 30 '14 at 16:59
  • Higher clock speed meant better performance has not been true since the P4 times (about 2003). – Hennes Dec 5 '16 at 13:33
  • As Ramhound pointed out you should start by comparing apples. So Haswell to Haswell. In order to get a grasp on the performance difference between different architectures you would have to try to get a good understanding of each or would have to rely on empiric data like benchmark results comparing them. In a best case you would try to understand what the benchmark actually benchmarks to have an idea of what their score indicates. – Seth Dec 5 '16 at 13:54

Whenever I chose a CPU for a new build I always go here: https://www.cpubenchmark.net/

I basically look at the scores that the CPUs get and find nitches of where you get a big price drop for similar performance if that makes sense. I usually go for high performance at a good deal but of course if your aim is something like lower power consumption for the performance I am sure there are charts out there for that too.

I like this method because it holds all manufacturers to the same level.

In terms of laptops, I would also look on here for how they score.

CPU speed is more than just the number in front of the GHZ by the way. That is simply how fast the processor is processing at a time but that doesn't take into account how MUCH it is processing at a time. I feel that benchmarking is the easiest way to see the differences without having to look into deep details.

  • Totally slipped my mind - done! – David Brossard Sep 30 '14 at 16:58

You seem to be comparing a "mobile" CPU with "ultra mobile" CPUs.

Ultra mobile CPUs have lower clockspeeds to give lower power consumption and lower heat dissipation allowing for thinner/lighter laptops. They have been arround for a long time but are much more commonly seen now due to the ultrabook craze.

You can still find more conventional laptops but they aren't what everyone is pushing as their headline products.

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