Come on. Just because you can't doesn't mean everyone is a liar.
My 280x can get easily over 21Mh/s each. Heck, my 7850 gets 11.9Mh/s right now.
My friend is running his pair of 290 at 28.7Mh/s each. He gets his 290x at 31.6Mh/s.
It runs at those hashes for days also BTW. Not just some start-up spike.
1. If you mine at 1GH, use VIP as your password.
2. If you mine at zhpool, use port 40001.
3. Make sure you use the latest cgminer from hvc.1gh.com.
4. Try using both -w 64 or -w 256 to see which is better for you.
I have been mining on zhpool for almost 2wks now @15.5Mhs per 290. Well, after reading your post I decided to go check out 1GH and see what kind of hash I could get there. Remarkably, I now get around 29Mhs on 1gh with VIP, even though I was only getting 15.5Mhs on zhpool with fixed diff(40001). I didnt change anything in my bat except the server address.
My question; whats with the difference in hash rates from the 2 different pools? Its nearly double...
Edit: Fixed port Typo