This thread is pretty old but I figured I'd add on to this thread for posterity as I'm troubleshooting the same issue. I have not figured out what's wrong with my system but your command has a minor typo in it that caused it to give no results. VGA should be capitalised as grep is case sensitive.

 

I'm using my own node of P2Pool. It took a while to setup, but no required fee is nice. It takes a few days to start getting a decent payout due to the Pay Per Share format but it's working out pretty well now. I like the peer to peer aspect of it so it's a bit more resilient to DDOS. Seems like almost every centralized pool has had an issue with DDOS attacks lately. The trick with getting it working well with LTC is to triple check your port configs both for your miner and your litecoind/wallet. Most instructions list the BTC ports which are different than the LTC ports.

I'm having the same trouble... Was thinking it might be my motherboard/CPU/RAM since it's an older setup with only 2GB of RAM. I'm hitting a max of 400kH/s but even that seems unstable.

I bought two identical cards at the same time and they both behave the same. While trying to tune one of the 7970's received the error below when trying to increase TC to 10240 from 8192. This was with an intensity of 13 and autofan. Was just following the tuning guide from https://github.com/ckolivas/cgminer/blob/master/SCRYPT-README Anyone know what LG is? I've never seen a reference to that setting before. Is buffer memory referring to the card's RAM or the system RAM?

[2013-04-10 03:21:52] Maximum buffer memory device 0 supports says 536870912
[2013-04-10 03:21:52] Your scrypt settings come to 671088640
[2013-04-10 03:21:52] Error -61: clCreateBuffer (padbuffer8), decrease TC or increase LG

Thanks for the help, hope we can figure this out...