My 8400GS can do these in around 2-3 hours, the 9800GT does them in 13 minutes.
You should get around 70-80 credits/WU. On slower cards it's around 700/day - not a huge amount but it's 700 you weren't getting before.
Maybe 2 problems...
Slower cards will notice a screen lag - you can stop this by downloading the latest BOINC Manager ( http://boinc.berkeley.edu/download.php ) currently 6.6.36, attach to the project ( http://boinc.thesonntags.com/collatz/ ), set project preferences to...
Use Graphics Processing Unit (GPU) if available 'yes'
Use Central Processing Unit (CPU) 'no'
(CPU version takes 4-5 hours if you want to do that, for the same credit)
In BOINC Manager - 'Advanced' > 'preferences' > 'processor usage' - untick 'Use GPU while computer is in use' box. Set the idle time to whatever you want (mines set to 3 minutes). The GPU will stop crunching as soon as you tap the keyboard and allow normal computer usage without screen lag. It will start again 3 minutes after the last keystroke. Only do this if you do have a lag problem.
The other problem, (which might not be as I'm not at the other PC that often to check) is that on restart the percentage restarts at 0%. Whether it actually does restart from 0 or from a checkpoint I don't know.
Quorum is 2 so you don't get instant gratification (ooer!)
This project's goal is to prove, or disprove, the Collatz Conjecture.
In a nutshell, the Collatz Conjecture states: For any number if the number is even divide by two else multiple by three and add one. Repeat. Eventually all numbers will reach 1.
Start with 3.
3 -> 3 * 3 + 1 = 10
10 -> 10 / 2 = 5
5 -> 5 * 3 + 1 = 16
16 -> 16 / 2 = 8
8 -> 8 / 2 = 4
4 -> 4 / 2 = 2
2 -> 2 / 2 = 1
It took 7 steps to reach 1.
Searches will start where the previous 3x+1@home project left off, beginning with the number 2,361,183,346,958,000,000,001
Note: This project is not for commercial purposes, nor it is related to any academic research. It was created because. That's it. Just because.