I recently get confused about graphics card brand, and i have a question does graphics card brand does matter? Is there any performance difference between a graphics card from elitegroup and xfx with same gpu?
Brand variances have more to do with warranty and features than anything else. The warranties vary a little bit (time of warranty mainly). Also, some brands give you more stuff 'in the box' such as SLI bridges, cables, etc.
Some brand specific models will have slightly altered clock speeds, or aftermarket cooling solutions that may let one model run a little cooler or quieter than others.
As far as performance, I've never seen that there's a performance difference worth sticking with any particular brand. I've owned graphics cards from several manufacturers over the years and have never had a problem. Lately I've been buying nVidia based GPUs from MSI. They tend to be less expensive, and in my experience perform just as well (and I've never had a problem with them).
Generally speaking, find the company that offers the best inclusive deal for the money. Also keep in mind, some models will be more expensive because they are "OverClocked". Depending on how much that model is actually overclocked (sometimes this is very minimal) it may not be worth any price difference at all.
Also be wary of the amount of memory on the graphics card. Depending on what you're doing, some older cards offer 512MB of RAM. The latest graphics cards will offer 1GB of RAM. This is probably optimal for current gaming. However, there are a few models available with 2GB of RAM, and they charge a pretty penny for them! It's not worth it to buy those at this point.