I am upgrading my old maximus 2 formula rig.
And i would like to know what is the difference between ram-s of different manufacturers?
Plus how big is the power consumption difference between ati-s 4870 and 6870?
I'm not sure what you mean by the RAM question. RAM can be found in different speeds, latencies, and operating voltages from a number of manufacturers. I stick to a few different brands though. Crucial, G.Skill, and Corsair have all been good to me. I don't know what your situation is, but it's not advisable to invest very much money in DDR2 these days. All current platforms use DDR3 and depending on your budget and timeline for a system upgrade it may not be worth it to buy DDR2.
TechReport reviews GPUs when they come out. You should check them out for the info
you want regarding the 4870/6870.