Archon shards are as follows

Tau Red +15% Power Strength
Tau Red +15% Power Strength
Tau Blue +75 Max Energy
Tau Yellow +37.5 Cast Speed
Tau Yellow +37.5 Cast Speed.

30% Strength is required for 100% armor strip with pillage.

284% idle, +30% [Archon Intensify], +60% Molt Augmented = 374%

So you need Normal Red, or 2 Tau Red to achieve 404% for 100% pillage strip.