- I have a 500watt power supply so if I added a card or two, would I need to upgrade the power supply (the current card already needs 500w)?
- What are some of the most cost-effective ATI cards these days? It seems that there is a point of diminishing returns with cost of the card/hashrate.
You can find the different devices used to mining here:
https://litecoin.info/Mining_hardware_comparison.
HD5850 and HD7950 are really worth getting, when it comes to the reward/cost; but they do pull a lot of W. Therefore a bigger and effective PSU would be recommended, e.g. x2 7950 would need atleast 600W PSU.
I know you don't really care that your hashrate is low, but I just want to make sure you understand. 70Mh/s is VERY low. We aren't even talking 10 pennies a day at this point, I don't think.
I can second that, it might even be less than that.