Huh? I thought "sick" was a negative term. If you refer to something as being "sick fast", are you implying that it's good, or are you implying that it's bad?
Nope, sick means good now. Actually it means very, very good.
Assuming you arent' being sarcastic, I will explain. "Sick", when used in the parlance of many home computer builders is a postive reference to the technical achievement and performance of their home built computers, also known as rigs. You might also see or hear such adjectives as wicked, nasty, thumping, jacked or my personal favorite, PHAT.
This can be confusing. As an example, one might describe their new computer build with the phrase, "This new gear is completely insane." Translated: "My new computer stretches the scope of my understanding of what cutting edge performance in new computer technology is possible". - It can be very puzlling and I appreciate the somewhat bewildered response to my orignial post. My apologees.