Since someone mentioned Jack Liam AKA asianbtc AKA lightningasic, I'll post my convo with him as it seems the price fluctuates quite a bit.

Jack:" i have USB cell. 300KHS, LA3M, 3MHS, LA6M 6MHS scrypt."
Price is "LA6M, usd5100+usd300 for express" <-----------------------------------------------------which means 6mh/s of gridseed units

This next quoted thing doesn't make much sense as it says "4 PCS", which could mean 4 of the LA3M............ each being 3MH/s of gridseeds.
Jack: "4 PCS LA3M. usd2750 including dhl express"

From my understand LA3M=10 gridseed units in a "cell" and LA6M is 20 gridseeds in a cell. He says all power supplies, cables, etc. are included.

I think the last quote is either in error or is a dam good deal. 4x LA3M cells, 40 gridseeds in total, for 2750usd($68.75 for each 5 chip gridseed)..........but 1x LA6M which is 20 gridseeds would be $5100........so something ain't right.

I have a friend in China that can get them for me, so I didn't ask Jack to clarify on the LA3M thing. I just let it drop since $5100 for an LA6M is far higher than advertised anywhere else, making Jack a bit shady to me. Well at least extremely greedy, if not outright shady.

Don't shoot the messenger, I'm just passing on info I have

I think you should try to get your GPu engine/memclock back to stock settings and tweak it from there. You've got them really low atm. I've also seen people using I-17 or even higher with the 290's

I have the same problem first trying yesterday.  Today just increase System RAM to 8GB and easily jump to 420Kh/s.  But I am not sure 4 GPU need 32GB or not LOL
setx GPU_MAX_ALLOC_PERCENT 200
TC increase to 24000 and OC the VCC with 50mV E 1000 M 1500.

I suggest you edit your post first and leave out your username/pw

Then try to lower the -w to 256 and edit your Thread concurrency to 8192