Got it!

Coins sent. Waiting for my account ^^

I get ~320MH/s @ 850/1000 with the same card at stock voltage.

I use latest drivers and poclbm gui with flags -v -w128 -f0.

You can adjust the voltage of this card with the latest Sapphire Trixx.

Oh, I hadn't seen it, sorry. 

Tycho, could it be posible to reset workers' shares counters individualy?? I'm testing differents cards at different speed and there is some workers I don't want to reset its stats. I hope it will be possible.
Thank you

Perfect now, ty

When I try to refresh balance in GUIMiner with my API it says Connection error. Some kind of bug?? Can you take a view for it Trycho? It works good for me 2 hours ago.
Thank you in advance

Hi,
You should use a dummy plug for the card whose don't have the monitor plugged. You don't have to have crossfire and I recomend to set the 4870 in the primary PCIe slot which you will use as primary.

The dummy plug simulate that there is a monitor plugged and you can use the 2nd card.

Here you have a link to make a dummy plug. You only need a DVI-VGA adaptor(which comes with every card) and some resistors.

http://www.geeks3d.com/20091230/vga-hack-how-to-make-a-vga-dummy-plug/

I hope it will help you. I have a 5850 in the primary slot and a 5770 with the dummy plug mining and it works for me perfect.

Do you have both in crossfire?
OpenCl doesn't appear in any of the cards in gpu-z ?

It seems that all our luck has gone in the past difficulty change. Long blocks  is common now. At least at night time(here in Spain gmt +2) it seems we have more luck than day time.
Is someone calling to teeth fairty to help us minning while we sleep?? Or it's only some kind of ghost giving us a lot of bad luck during day? Lol, it should be the bit-ghost, who play with our graphic cards doing they work without sense. 
Well, all of us should had a rabbit leg above the case or the monitor, it will be good for all.
(Yes, if someone is thinking about... I was a little bit bored and thought about our lately bad luck  )

AMD Athlon 64 X2 4600+ running on W7 Ultimate 32bit, I get ~60% runing poclbm gui pre in 2 graphic cards(5770 & 5850). I had 100% but after set afinity only in one core, CPU usage low to ~60%

Yes, but I have a 5850 and a 5770 so I couldn't do crossfire and I have to use the dummy plug.

Yes, a dummy plug is to simulate a 2nd monitor. As I have only 1 monitor I must tu use a dummy plug in the second card.
Here you have to make easyly a dummy plug only with the dvi-vga adaptor and some resistors.
http://www.geeks3d.com/20091230/vga-hack-how-to-make-a-vga-dummy-plug/
There you have the electronic scheme for the resistors.

Hi, I have just installed 2nd card few days ago and I hadn't to re-install drivers. It detects 2nd card automaticly but I had to use a dummy plug for enable OpenCL in the 2nd card.
I use 11.2 in W7 32bits.
Anyway you could uninstall drivers package and reinstall it to be sure

I could plug both cards(5850 & 5770) and now they work perfectly with dummy plug, thank you TenthReality.
It's better mining than have a card useless.

Ok, thanks TenthReality, tomorrow I will go to buy some resistors and I will try that.

Ok thanks, do you know if dvi-vga adaptor that comes with the graphic card would do the same use?

I have also a question about that. I have a 5850 and a 5770 in a mobo Asus m2n-e sli. It has 2 pci-e slots so I can plug both cards but when I use the miner it only shows me the first one and in GPU-Z only the card that is in the primary slot has OPENCL. There is some way to use both to miner? At least I will have to use only 5850 but it would be great if I could use both.

Ok, I hope to remember about it in a month 

I have done about 12 BTC in this 5 days 24/7 but I have been reading that it also depends of the luck, some days you get more and some days less. I will have an opinion about the end of the month