I think you might be missing the point. In today's market, the intent of mining with compacs is usually for educational purposes and/or fun. Anyone expecting to make a legitimate profit on compacs is either hoping to win the lottery solo mining or simply misinformed.
Anyway, spazzdla is correct. If your intent is to USB mine for whatever reason, Sidehack's GekkoScience Compac is the way to go.
In my first post i clearly indicated that the only two things those sticks are good for are instamining and learning
. I answered to spazzdla's post because i felt it kinda looked like he said it was a good thing to mine with a compac, while it can only be seen as an educational tool (in my personal opinion). Maybe i used the wrong wording in my post.
That being said: if you want to learn how to mine, i don't think there's a difference between an old U2 or a compac. Neither of them will give you enough satoshi's to make a withdrawal from a pool, neither of them will have a significant chance of hitting a block, and both of them will have enough hashpower to join a pool and see some shares rolling in (altough you won't make enough to actually withdraw your profits).
Just my personal opinion tough.
Well a compac stick has a decent shot at a PPC block via solo mining. I know I hit a few with them.
They also look pretty.
They run silent when clocked to 150mhz
Will you turn a profit most likely no. I don't feel like the math it is early but in my head quickly the chance of hitting 2 PPC blocks in a year with 1 stick is 10% .
Can they turn a profit yes if you Hit a PPC block 2 times and you are running the stick on a work PC. ie no power cost.
So a 10% to make a profit with free power is close.
Now if you have free power they are much better then playing the 4 digit lottery offered in the usa.
a 4 digit number in the usa gives you 5000 to 1 and costs 50 cents in some states.
your cost would be 182-183 usd per year and you should hit it once every 27 years for a loss of 5000.
your cost with a compac is 25-35 dollars
if you run it at 8gb on a free power setup you have a 1,442,256 shot in 1 day or once every 3951 years you hit a block. collecting 600 x 12.5 = 7500 bucks
you cost would be 25-35 dollars but 3951 years with normal luck is a long time.
100 sticks would be 2500-3500 usd if you could scatter them about all at free power you would hit a block in 39.51 years and collect 7500 for the 2500-3500 cash you paid for the sticks. this is actually not realistic because I froze diff at current levels