Some questions as a newbie!

[samyaza]

Hello everybody! I came across this mining thing and I decided to give a try. There are some few tutorials out there and I learned the basics. However I want to understand more about how this work.
I use mining.bitcoin.cz, the standard Bitcoin wallet downloaded on my computer, a mining proxy and that's all.
However my results are no good at all.
I have a poor video card, a nVidia GT610. I'm not a gamer, but I decided to give a try with my actual video card.
With the best setup I get like 10.2Mhash/s. I noticed this is very low compared to what other people can do.
I want to ask you all a question. How about if I get another ATI videocard? I was thinking to get a Sapphire ATI 7770, and later a sister for her because my motherboard is an Asus P8B75-V and has 2 pci-e slots 16x and it supports crossfire.
Can anybody estimate how much Mhash/s can I do with a single ATI Sapphire 7770? But with a crossfire made with ATI 7770?
Also I want to understand where my bitcoins goes? In the mining.bitcoin.cz account I have different fields in my account section: Estimated reward: with red.. and it goes up when I have a peer accepted, but soon it drops, unconfirmed rewards, and confirmed rewards.. always on 0! Can anyboy explain me how can I make bitcoins with this system?
Also can anybody estimate how many bitcoins can I make in a hour using a single ATI Sapphire 7770? But using a 2 ATI's 7770 in Crossfire mode? Thank you very much to everybody, and I hope to enjoy this wonderful community!

[odolvlobo]

This might help you: https://en.bitcoin.it/wiki/Mining_hardware_comparison

As for calculating the revenue, do a search for "bitcoin mining calculator" and pick one that calculates the information you are looking for.

[samyaza]

Hello, thank you for reply. I tried some different mining calculators but I got some big ridiculous results. Well whatever. I had some other issues too. My computer crash every time I push the stop mining button. On the CPU everything is fine but on the GPU (nVidia GT610) is blocking every time. However I don't understand what is the real Mh/s rate. The software running on the computer shows a 10-12Mh/s rate, but on site I have like 0.5 Mh/s ....once in a while 1 share accepted, then I get few Bitcoins, then they start to drop till they reach 0. I don't really get it. However I don't know if is worth mining with my videocard, but I tried just to get some experience.
The temperatures on the GPU goes up to 70 Celsius degrees, and is full load on 98%, I ruin it for nothing. I want to try a dual video card setup, but still I'm not clear how efficient can you go. In my country the electricity is not so expensive,but also as everybody I have a target of bitcoins to make. Seems more easy to make money selling shovels (rigs) than using it.