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Core i5-6400 vs i7-8665U


Description
The i5-6400 is based on Skylake architecture while the i7-8665U is based on Whiskey Lake.

Using the multithread performance as a reference, the i5-6400 gets a score of 174.1 k points while the i7-8665U gets 109.7 k points.

Summarizing, the i5-6400 is 1.6 times faster than the i7-8665U. To get a proper comparison between both models, take a look to the data shown below.

Specs
CPUID
506e3
806ec
Core
Skylake-S
Whiskey Lake-U
Architecture
Base frecuency
2.7 GHz
1.9 GHz
Boost frecuency
3.3 GHz
4.8 GHz
Socket
LGA 1151
BGA 1528
Cores/Threads
4/4
4/8
TDP
65 W
15 W
Cache L1 (d+i)
4x32+4x32 kB
4x32+4x32 kB
Cache L2
4x256 kB
4x256 kB
Cache L3
6144 kB
8192 kB
Date
September 2015
April 2019
Mean monothread perf.
48.05k points
35.19k points
Mean multithread perf.
174.05k points
109.72k points

AVX2 optimized benchmark
The benchmark in mode III (AVX2), like AVX1, is optimized to used 256 bits registers beside the second version of the Advanced Vector Extensions (AVX). The first AVX2 compatible CPU was released in 2013.
Monothread
i5-6400
i7-8665U
Test#1 (Integers)
21.1k
14.38k (x0.68)
Test#2 (FP)
18.28k
13.43k (x0.74)
Test#3 (Generic, ZIP)
4.22k
2.87k (x0.68)
Test#1 (Memory)
4.45k
4.49k (x1.01)
TOTAL
48.05k
35.19k (x0.73)

Multithread

i5-6400

i7-8665U
Test#1 (Integers)
80.03k
47.22k (x0.59)
Test#2 (FP)
71.1k
46.99k (x0.66)
Test#3 (Generic, ZIP)
16.19k
10.08k (x0.62)
Test#1 (Memory)
6.73k
5.42k (x0.81)
TOTAL
174.05k
109.72k (x0.63)

Performance/W
i5-6400
i7-8665U
Test#1 (Integers)
1231 points/W
3148 points/W
Test#2 (FP)
1094 points/W
3133 points/W
Test#3 (Generic, ZIP)
249 points/W
672 points/W
Test#1 (Memory)
104 points/W
361 points/W
TOTAL
2678 points/W
7314 points/W

Performance/GHz
i5-6400
i7-8665U
Test#1 (Integers)
6394 points/GHz
2996 points/GHz
Test#2 (FP)
5539 points/GHz
2799 points/GHz
Test#3 (Generic, ZIP)
1279 points/GHz
599 points/GHz
Test#1 (Memory)
1348 points/GHz
936 points/GHz
TOTAL
14560 points/GHz
7330 points/GHz

Monothread performance graph
Monothread performance graphics gives the performance vs time. They are useful to measure the time it takes to the CPU to reach the maximum performance.

Usually, CPU's performance will be steady during these tests but if it has a slow frequency strategy, the first samples will show a lower score.


Test#1 (Integers) [points vs time]

grafica bm.hardlimit.com


Test#2 (FP) [points vs time]

grafica bm.hardlimit.com


Test#3 (Generic, ZIP) [points vs time]

grafica bm.hardlimit.com


Test#1 (Memory) [points vs time]

grafica bm.hardlimit.com

Multithread performance graph
Multithread graphs measure the performance against a heavy load during certain time.

If CPU's TDP doesn't limit the frequency and the machine is properly cooled, performance should remain steady vs time. Otherwise, the performance score will oscillate or decrease over time.


Test#1 (Integers) [points vs time]

grafica bm.hardlimit.com


Test#2 (FP) [points vs time]

grafica bm.hardlimit.com


Test#3 (Generic, ZIP) [points vs time]

grafica bm.hardlimit.com


Test#1 (Memory) [points vs time]

grafica bm.hardlimit.com

Hardlimit Benchmark Central - Ver. 3.11.4