GIF image optimization

Recently I had to optimize a gallery of some 20,000 GIF and looking for programs that can do massive way (batch process), I was doing a lot of testing with several of these applications and finally chose three programs that enable such optimizations.

• Absolute GIF Optimizer. It is most convenient to use, will you indicate a folder and practically with a button optimizes you all. ( official website of Absolute GIF Optimizer )
• Advanced GIF Optimizer. It optimizes GIF folder by folder, ie not automatically allow subfolders. In the trial version only optimizes 20 images every time the button is pressed optimize why you should go giving the button until optimizes all images in a folder. ( official website of Advanced GIF Optimizer )
• RIOT. It's a little more complicated, you can tell that want to optimize a folder and all its subfolders, but optimized GIFs saves only one folder. So there you go optimizing GIF folder by folder. Allows two different types of compression. It also has the pluggin version of XnView and GIMP. ( RIOT official website )

These are the screenshots of the three programs. If you are curious to see them, click on the image to enlarge.

Absolute GIF Optimizer

Advanced GIF Optimizer

RIOT in XnView

Tests performed with the 3 GIF optimizers highlights

On the compressibility depends on the images, but of the three tests with the three programs these are the results:

Test 1, 205 optimizing GIF files.
Original: 20,791,385 bytes
Compressed with Advanced GIF Optimizer 4: 20,785,193 bytes
Compressed with the Absolute GIF Optimizer 1.01: 20,785,193 bytes
Compressed with XnView and pluggin RIOT 2 (NeuQuant-Neural net): 20,211,232 bytes
Compressed with XnView and pluggin RIOT (Xiaolin gu-color): 10,649,543 bytes
Test 2, 103 optimizand GIF files.
Original: 4,649,692 bytes
Compressed with Advanced GIF Optimizer 4: 4627374 bytes
Compressed with XnView and pluggin RIOT: 4,564,074 bytes
Compressed with the Absolute GIF Optimizer 1.01: 4,507,113 bytes
Test 3, optimizing GIF 20,453 !!!
Original: 1,895,003,874 bytes
Compressed with Advanced GIF Optimizer: 1,891,304,678 bytes
Compressed with the Absolute GIF Optimizer: 1,891,261,124 bytes
Compressed with XnView and pluggin: 1,064,442,248 bytes

Conclusions:

To optimize GIF files massively, the best program to compress GIF files is the RIOT, with compression option "Xiaolin gu-color." It is a bit heavy to do it folder by folder, but the result is amazing and apparently there is no difference between the original image and the compressed image.
Worst of all the the Advanced GIF Optimizer, which besides being uncomfortable to use, compresses very little.