I`m buying new system soon, and got much of it decided...I really like Gigabyte GT ODIN 550W PSU,
in my new system I will have only one HD3870 and maybe add another some time later...
So my PSU would totally handle all this(+Core2Duo 2gigs ram, one HDD, one DVDRW)?
http://www.legitreviews.com/article/605/13/ --> only 305w for crossfire + intels quad!

But as I said I like it and would like it to last for me, so can I expect that it could support some stronger cards or crossfire systems that will come in next 3-4years?
I know it is difficult question, who know what will happen in future, but as I see (and I like it) the industry is going towards reducing power demands of components, lowering nm process for transistors, making some features on motherboards and similar...

anyone?

.... Maybe. It's because I don't expect for general computer system power usage to lower because also the components get faster as well. In my opinion, lower nm + faster speed = same power consumption , I think.

Yes you can crossfire another Radeon 3870 on the motherboard in regards to PSU limits, however, I don't think you can crossfire two 8800GTX's on that PSU. It's because there are also other components, such as USB devices, extra fans, etc.

A kilowatt of PSU is just bragging rights... what really matters for a PSU is its quality and the number of amps on the +12v rail ... i believe 40 amps on th +12v rail will more than hold your rig together for 4 to 5 years easily.... your ODINs got 41 amps, so don't worry.

3870 In Crossfire will work but if you will be getting another GPU card in the future you will have to look at the power requirements if your going to SLI or crossfire it because 550W is a little on the low side for a dual GPU pc.

Here's where I go for answers to that kind of question:
http://www.atomicmpc.com.au/forums [...] t=9354&p=0

According, two 3870's need about 160 watts. Call it 15 amps.

Yes, I know that 12 volts X 15 a = 180 watts. Allowing 10% for Mr. Murphy is my way of placating him.

Or simply get a single nVidia 8800GTS 512MB (G92) video card. The following article shows that it beat two CrossFired Radeon 3870s (or match it) in all but two games; BioShock & Call of Jaurez.

Two vs. Three: Zotac GeForce 9800 GX2 Against 3-Way CrossFire ATI Radeon HD 3870

A single 8800GTS 512MB (at stock speed) consumes 99w of power. Thats compared to 162w for two Radeon 3870s.

Nvidia GeForce 9600 GT: Worthy Rival to ATI Radeon HD 3000 (page 7)

ok, ok...thanks guys...
I like the quality of image reproduction and silence of ati cards...
also there is price/performanse ratio and x38 board for crossfire, where ati is better choice...

I'm not very familiar with Gigabyte's PSU's and who the OEM is that makes them, I'd do a google search for some reviews just make sure there's nothing flakey with them. Antec's Earthwatts units are great in the 500w range if you want a quality alternative to look into, as well as Corsairs 520w.

If you're going to Crossfire grab an X38 board. Basically the only significant difference between them and P35's are that the X38's have TWO PCI-E x16 lanes that both run at full x16 speed/electrical. P35's can have lanes for your graphics cards, except one will only run at x4 speed/electrical and that will gimp even a 3850.

Cheers and good luck!