I spent a little time trying to figure out how much to pay for cards on eBay. I took 10.15 pounds of cards, removed the metal brackets and had 7.95 pounds of "cleaner" cards.
I cut off the edge fingers. They weighed 111.5 grams.
I processed a lot of 500 grams of edge fingers and came up with almost exactly 2 grams of gold. My 111.5 grams of edge fingers from +/- 10 pounds of cards was worth roughly $18.00 in gold content.
Trimmed finger cards can be sold to Boardsort for $31.00. The total value of 10 pounds is thus $31.00 + $18.00 = $49.00.
Now you have to figure the cost of acid, peroxide, buckets, air bubbler, bleach, glassware, time, etc.
Those costs vary for each of us, as does the value of our time. The results from my edge fingers will vary from yours due to skill level, technique, age and type of fingers and many other factors I'm not enumerating here.
If you process lots of material the relative cost of these extra items is spread across more revenue making it somewhat more profitable.
You asked about processors. My results show that a fiber Pentium 3 is worth about $0.25, while a 486 is worth $8.33. These numbers are from MY experience and it will vary for those who have better or worse procedures than mine. These numbers are for the gold content only and don't take in to account any expenses or time involved in getting the gold out of them.
It took me roughly 8 minutes to put this all in a post for you. How much time are YOU willing to spend reading the countless hours of posting that is available here for you?
If you are willing to put in the work you can learn what I have learned in my two plus years of reading almost EVERY post on this forum.