The carbon fiber most of us are familiar with starts with a dry woven fabric, gets placed in a mold, is infused with resin, and cured to a carbon fiber part. Something along the lines of this:
Forged carbon fiber on the other hand, is made from either a paste or chopped up carbon fibers. There is no set pattern to it as the fibers are arrange entirely randomly, making each part unique to itself. The finished product has a totally completely different look to the commonly known carbon fiber weave, giving it more of a marble look:
Besides the difference in aesthetic, what is another difference between woven carbon fiber and forged carbon fiber? Carbon fiber aficionados will quickly point out that woven carbon fiber can make a stronger, more durable part because of the control you have on the tensile strength that is given by the weave. This does not mean forged carbon fiber is a weak composite; after all it still is carbon fiber.
So where dose forged carbon fiber have a big advantage over woven carbon fiber? Forged carbon fiber really shines in making parts with a 90 degree angle or any weird shapes where the weave of the woven carbon fiber might become distorted.
If you are building a race car, you may want to stick with woven carbon fiber, and if you are building a street car or show car you can't go wrong with either forged carbon fiber or woven carbon fiber. In the end, each variant has its pros and cons and will depend entirely on the application it is being used for.