First off, 99 threads relates to how many mining threads (CPU) you are running, you should never run more threads than you have physical cores (or logical threads), i.e. in your case : 4.
That aside, you should try GPU mining with a pool. You can use cgminer as normal (as you would of used it for Bitcoins) but just change your conf file to point at a pool and start cgminer with the --scrypt option and you’re good to go.
Scrypt mining (as opposed to SHA-256 of Bitcoin) works out to be 1000x less. So as a rough estimate you should be seeing (before tweaking) mining speeds in the region of 180-220khash,.
I’ve skipped quite a lot, but as you’ve said you’re fairly experienced with BTC mining you should be fairly competent to work out what to do once you have a pool address and the mining running :P
So a quick roundup:
Look in the ‘Mining’ section of this Forum for a Pool.
Sign up to a pool.
Create / edit the ‘My Worker’ substituting in values you want.
Download cgminer
Create a bat enveloping cgminer.exe
Bat:
[code]cgminer -o pooladdress:poolport -u username.workername -p password --scrypt[/code]
Run the bat, have cgminer up and running / mining.
Click on the cgminer window, press the “S” key, then press the “W” key, then press the Enter Key twice.
Now you have a cgminer.conf stored in your cgminer folder with all the configurations.
You can now simply start cgminer by double pressing cgminer.exe, and you can start tweaking the conf to eek out more khash from your GPU.
Best of luck and question away and I’ll try and help ^^