How can an intel i5 CPU outperform a same gen i7 CPU?

I get computer architecture/cores/threads, etc. impacts performance, but when looking to spec a new laptop, can someone explain how the 8th gen intel i5 8350 seems to outperform the i7 8550?

http://cpu.userbenchmark.com/Compare/Intel-Core-i7-8550U-vs-Intel-Core-i5-8350U/m320742vsm388461

These comparisons are made, ostensibly, using the same or similar machines, both have 4C/8T, with the i7 offering a slightly better base and max clock rate. Essentially, other things equal, superior clock rate is resulting in inferior performance.

Chris

Posted 2018-05-08T22:42:38.940

Reputation: 181

I'd expect with largish samples, differences in machine architecture would fall out. I take it then, your basic answer is "it shouldn't" – Chris – 2018-05-08T22:59:19.323

Answers

Both of these CPUs dynamically adjust their core speeds based on power consumption and core temperature. If both of these CPUs are cooled and powered with comparable hardware, they will perform pretty much the same. Intel had to draw the line between i5 and i7 CPUs somewhere, and as a result, the difference between the best i5 CPU and the worst i7 CPU in a line of related CPUs won't be very much.

David Schwartz

Posted 2018-05-08T22:42:38.940

Reputation: 58 310

so if dropped into the same machine, they'll perform similarly with an epsilon roughly equal to the difference in in clock rates (which isn't that much) – Chris – 2018-05-08T23:03:02.110

@Chris Right. The clock speed difference may be none because under most realistic conditions, both CPUs will limit their speed based on their temperature and power consumption. – David Schwartz – 2018-05-08T23:05:11.513

@DavidSchwartz You make a good point, but the i7 would run “faster” at the same temperature. But there are to many other variables to take into account. A high amount of extremely fast memory could make some significant improvements to floating point calculations. – Ramhound – 2018-05-08T23:07:51.890

@Ramhound The i7 won't run faster at the same temperature. It may even run slower. As each CPU reaches temperature, it throttles to maintain safe temperature. There's no particular reason to expect the i7 to throttle to a higher speed than the i5. – David Schwartz – 2018-05-08T23:20:57.757

These comparisons are made, ostensibly, using the same or similar machines, both have 4C/8T, with the i7 offering a slightly better base and max clock rate.

It isn’t clear how you made this determination. Based on the listed OEM models that doesn’t seem to be the case.

I get computer architecture/cores/threads, etc. impacts performance, but when looking to spec a new laptop, can someone explain how the 8th gen intel i5 8350 seems to outperform the i7 8550?

Insignificant sample size explains the results. Only 99 i5 users have submitted their benchmarks. Over 10,000 i7 users submitted their results. Any number of conditions could invalidate a sample size that small.

A sample size of 99 compared to 10,300 invalidates the comparison. The i7 has an insignificant higher based frequency of only 0.1 GHz, and the an additional 0.4 GHz greater boost frequency is debatable due to it being a mobile product. The boost frequency is entirely dependent on temperature.

Ramhound

Posted 2018-05-08T22:42:38.940

Reputation: 28 517

like I'd mentioned above, I'd made an assumption that over a large-ish sample, differences in architecture would fall out. my basic question was whether there was something I was missing that could cause the difference aside from this source of variation – Chris – 2018-05-08T23:02:26.530