Thank you for the answers
@JayC OCed core at 950 MHz gives me 170+ but the temperature is too high - 82C and I want to keep it <80. Maybe if i improve the airflow inside the box i will be able to keep the core at 950MHz 24/7 but still the difference is not that big...
I'm not from US either. I'm from Bulgaria, Eastern Europe and here local dealers sell 5850 for $288
That's why im currently looking to buy used card and a power supply. And... yeah maybe I will stick with my 5770 + hopefully 5850 as this will be the cheapest mining upgrade.
1. your motherboard DOES support crossfire, why do you think it doesn't...? X38 is an Intel chipset, Intel chipsets = crossfire, Nvidia chipsets = SLI, but yeah, you don't NEED crossfire in this case...
2. you don't need an 850w PSU for crossfire, a good quality 550w to 650w will be fine, something like a Corsair TX650, the key with PSUs is the quality, a reputable brand will usually output the rated wattage, a crappy cheap brand will usually not output the advertised wattage...
3. add this to the end of your command line and your MH/s should jump over 200+ " -v -w 256 ", without the quotes of course, with that you should be able to lower your OC some and still get a decent MH/s, also, if you're not, set your fan to 100%...
5850s seem to be the sweet spot for mining and I think the vendors are catching onto this, you know, the whole supply and demand thing, prices seem to actually be going up on 5850s instead of going down on them like it should with an older card, the 5850 also uses less power than a 5830, even though the 5830 is the least expensive of the three 5800 series cards, it actually uses about as much power as a 5870 but gives you half the hashes, so in the long run the 5850 is the best card by far of the three...
I run my 5850 at 925/500 and get 330+ MH/s, this is my main miner on my kids' computer so it mines about 20 hrs a day, I need another card quick though, my other card is a 4890 and it uses a lot of power, runs very hot (shadercore runs at 100°+) and only pulls 90+ MH/s, not very efficient at all, even a 5830 would be an improvement...