Hi
After 8 years of services, I finally changed my old Athlon for a new one.
Christmas gift from last 2 years Works Council and annual bonus from last 2 years put aside, I was able to buy an AMD Ryzen 9 3900X 
So I’ve executed benchmarks and I’m a little bit surprised.
******** Start testing of FreehandStrokeBenchmark *********
Config: Using QtTest library 5.11.3, Qt 5.11.3 (x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 8.3.0)
PASS : FreehandStrokeBenchmark::initTestCase()
QWARN : FreehandStrokeBenchmark::testDefaultTip() KoColor debug runtime checks are active.
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 1 Time: 2365 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 2 Time: 1390 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 3 Time: 1032 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 4 Time: 861 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 5 Time: 752 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 6 Time: 696 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 7 Time: 671 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 8 Time: 644 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 9 Time: 622 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 10 Time: 603 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 11 Time: 605 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 12 Time: 572 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 13 Time: 610 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 14 Time: 601 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 15 Time: 594 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 16 Time: 584 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 17 Time: 577 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 18 Time: 591 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 19 Time: 581 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 20 Time: 599 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 21 Time: 596 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 22 Time: 581 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 23 Time: 603 (ms)
QDEBUG : FreehandStrokeBenchmark::testDefaultTip() Cores: 24 Time: 612 (ms)
PASS : FreehandStrokeBenchmark::testDefaultTip()
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 1 Time: 3194 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 2 Time: 1830 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 3 Time: 1321 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 4 Time: 1070 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 5 Time: 914 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 6 Time: 807 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 7 Time: 742 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 8 Time: 708 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 9 Time: 664 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 10 Time: 649 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 11 Time: 615 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 12 Time: 629 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 13 Time: 577 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 14 Time: 571 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 15 Time: 601 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 16 Time: 558 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 17 Time: 546 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 18 Time: 569 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 19 Time: 572 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 20 Time: 521 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 21 Time: 571 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 22 Time: 528 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 23 Time: 569 (ms)
QDEBUG : FreehandStrokeBenchmark::testSoftTip() Cores: 24 Time: 579 (ms)
PASS : FreehandStrokeBenchmark::testSoftTip()
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 1 Time: 4087 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 2 Time: 2314 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 3 Time: 1628 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 4 Time: 1313 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 5 Time: 1114 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 6 Time: 977 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 7 Time: 893 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 8 Time: 835 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 9 Time: 781 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 10 Time: 744 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 11 Time: 715 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 12 Time: 707 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 13 Time: 694 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 14 Time: 675 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 15 Time: 659 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 16 Time: 630 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 17 Time: 619 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 18 Time: 633 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 19 Time: 614 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 20 Time: 593 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 21 Time: 587 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 22 Time: 575 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 23 Time: 566 (ms)
QDEBUG : FreehandStrokeBenchmark::testGaussianTip() Cores: 24 Time: 587 (ms)
PASS : FreehandStrokeBenchmark::testGaussianTip()
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 1 Time: 2513 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 2 Time: 1443 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 3 Time: 1089 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 4 Time: 892 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 5 Time: 768 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 6 Time: 708 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 7 Time: 668 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 8 Time: 651 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 9 Time: 632 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 10 Time: 610 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 11 Time: 600 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 12 Time: 572 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 13 Time: 560 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 14 Time: 578 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 15 Time: 591 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 16 Time: 573 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 17 Time: 589 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 18 Time: 577 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 19 Time: 590 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 20 Time: 593 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 21 Time: 598 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 22 Time: 613 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 23 Time: 597 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectangularTip() Cores: 24 Time: 569 (ms)
PASS : FreehandStrokeBenchmark::testRectangularTip()
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 1 Time: 7834 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 2 Time: 4112 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 3 Time: 2860 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 4 Time: 2222 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 5 Time: 1835 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 6 Time: 1583 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 7 Time: 1403 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 8 Time: 1276 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 9 Time: 1186 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 10 Time: 1101 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 11 Time: 1031 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 12 Time: 1011 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 13 Time: 983 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 14 Time: 945 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 15 Time: 916 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 16 Time: 907 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 17 Time: 908 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 18 Time: 844 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 19 Time: 826 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 20 Time: 836 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 21 Time: 804 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 22 Time: 811 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 23 Time: 779 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectGaussianTip() Cores: 24 Time: 797 (ms)
PASS : FreehandStrokeBenchmark::testRectGaussianTip()
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 1 Time: 5200 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 2 Time: 2945 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 3 Time: 2075 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 4 Time: 1635 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 5 Time: 1370 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 6 Time: 1192 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 7 Time: 1081 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 8 Time: 993 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 9 Time: 922 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 10 Time: 875 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 11 Time: 840 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 12 Time: 832 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 13 Time: 804 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 14 Time: 779 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 15 Time: 762 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 16 Time: 785 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 17 Time: 748 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 18 Time: 744 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 19 Time: 683 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 20 Time: 688 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 21 Time: 651 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 22 Time: 684 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 23 Time: 683 (ms)
QDEBUG : FreehandStrokeBenchmark::testRectSoftTip() Cores: 24 Time: 671 (ms)
PASS : FreehandStrokeBenchmark::testRectSoftTip()
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 1 Time: 7217 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 2 Time: 3930 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 3 Time: 2715 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 4 Time: 2170 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 5 Time: 1816 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 6 Time: 1585 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 7 Time: 1448 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 8 Time: 1315 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 9 Time: 1229 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 10 Time: 1177 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 11 Time: 1156 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 12 Time: 1201 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 13 Time: 1110 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 14 Time: 1107 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 15 Time: 1097 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 16 Time: 999 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 17 Time: 995 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 18 Time: 947 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 19 Time: 981 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 20 Time: 996 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 21 Time: 995 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 22 Time: 988 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 23 Time: 982 (ms)
QDEBUG : FreehandStrokeBenchmark::testStampTip() Cores: 24 Time: 1035 (ms)
PASS : FreehandStrokeBenchmark::testStampTip()
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 1 Time: 7366 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 2 Time: 7250 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 3 Time: 7224 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 4 Time: 7079 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 5 Time: 7001 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 6 Time: 7283 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 7 Time: 7340 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 8 Time: 7249 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 9 Time: 7281 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 10 Time: 7233 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 11 Time: 7172 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 12 Time: 7199 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 13 Time: 7441 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 14 Time: 7348 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 15 Time: 7210 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 16 Time: 7071 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 17 Time: 7458 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 18 Time: 7376 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 19 Time: 7240 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 20 Time: 7389 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 21 Time: 7338 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 22 Time: 7176 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 23 Time: 7424 (ms)
QDEBUG : FreehandStrokeBenchmark::testColorsmudgeDefaultTip() Cores: 24 Time: 7549 (ms)
PASS : FreehandStrokeBenchmark::testColorsmudgeDefaultTip()
PASS : FreehandStrokeBenchmark::cleanupTestCase()
Totals: 10 passed, 0 failed, 0 skipped, 0 blacklisted, 368486ms
********* Finished testing of FreehandStrokeBenchmark *********
For some brushes, after 16 or 17 Cores, performances are degraded…
Is it normal ?
Another question: is RAM have an impact on executed test?
I ask question because computer is just build, and currently DDR4-3600 is running at 2666 (I need to check what happen in UEFI)
And results are just a little bit slower than results for Ryzen 7 3700X from @Deevad running with DDR4-3200
Also tested to compil Krita (4.3 branch), that’s fast 
$ make clean
$ time make -j24
real 6m44,041s
user 124m29,436s
sys 12m28,411s
Grum999