Cordura® fabric 1000D is extremely abrasion and tear resistant. The yarn is air-texturised creating a matt and structured appearance. Provided a proper weaving pattern is being used Cordura® fabric is a good bit more abrasion resistant than oxford nylon or polyester fabrics of a similar weight. With adding only 30% of extra weight 1000D Cordura® fabric shows a tensile strength which is about 2.5 times stronger than the one of 420D oxford nylon. "
What does 1000D mean in the real world of backpacks?
A trekking pack made entirely from 1000D Cordura® fabric turns out to be approximately 8-10% heavier but 30-40% more abrasion resistant than a model built from 420D or 500D nylon fabric. For the extra 10% which is less than 300 grams you get a pack body which is close to impossible to wear out. Of course no pack can withstand constant abuse. Eventually some part will always fail. If you go for 1000D it will most likely not be the fabric!