LOSSLESS PNG COMPRESSION BENCHMARKS

This is a place where I'll store various benchmarks on lossless PNG compression. While I'm normally okay with stripping metadata chunks on a case-by-case basis in my archiving, these tests are going to revolve around purely lossless compression when possible.
If you're interested in visually lossless (transparency-lossy) compression, another really good benchmark resource (by the author of pingo) can be found here.

MY BUILD

Intel i7-6850k 4.3MHz
ZOTAC GTX 980ti AMP! Extreme
32GB DDR4 RAM

Tested using PowerShell's Measure-Command{}

COMPRESSORS & PARAMETERS

advdef (2.1)

-z -4 -i 25 -f (IMAGE)

advpng (2.1)

-z -4 -i 25 -f (IMAGE)

DeflOpt (2.07)

-b/d/k/f (IMAGE)

ECT (0.8.2)

-9 --strict -keep --mt-deflate=12 (IMAGE)

ECT Genetic (0.8.2)

-9 --strict -keep --allfilters-b --mt-deflate=12 (IMAGE)

OptiPNG (0.7.7)

-o7 -preserve (IMAGE)

oxipng (2.1.6)

(IMAGE) --zopfli --threads 12 --interlace 0 --keep=tRNS,gAMA,cHRM,sRGB,iCCP,acTL,fcTL,fdAT,tEXt,zTXt,iTXt,bKGD,pHYs,sCAL,sBIT,sPLT,hIST,tIME,sTER,oFFs,vpAg --preserve

pingo (0.98.41)

-lossless -s9 -multiblocks=12 -nodate -nostrip (IMAGE)

pngcrush (1.8.11)

-ow -brute -reduce -save (IMAGE)

PngOptimizerCL (2.5)

-file:"(IMAGE)" -KeepFileDate -KeepBackgroundColor:K -KeepTextualData:K -KeepFrameControl:K -KeepPhysicalPixelDimensions:K

PNGOUT (Feb 13 2015)

(IMAGE) (IMAGE) /k1 /kp /kt /y

pngquant (2.12.2)

-o (IMAGE) --ext=.png --force --speed=1 --quality=100-100 -- (IMAGE)

pngwolf (1.1.2)

--in=(IMAGE) --out=(IMAGE) --max-evaluations=1 --estimator=libdeflate,level=12 --out-deflate=zopfli,iter=25

TruePNG (0.6.2.5)

/o3 /i0 /g2 /md keep all /t /tz /y (IMAGE)

ZopfliPNG

-m -y --iterations=25 --filters=0meb --keepchunks=tRNS,gAMA,cHRM,sRGB,iCCP,acTL,fcTL,fdAT,tEXt,zTXt,iTXt,bKGD,pHYs,sCAL,sBIT,sPLT,hIST,tIME,sTER,oFFs,vpAg (IMAGE) (IMAGE)

IMAGE #1

Digital drawing from my friend Kriztian of one of his characters, Aristora.

Medium color amount, flat background, some repeated sections

RESULTS

Time