750W PSU for 3870x2 CF ?

You need only 550W to run them both, so you should be fine.

You have one already in there or are you buying two?

I will buy one to test out perfromance and if everything will be fine I plan buying second one.

What is your budget for a card? Why not buy a better single card instead of buying such an old one?

a gtx570/hd6950 would be the obvious choice than to go xfire with a pretty outdated card.

6950 costs 4-5k czk but 3870x2 is possible to get for 1k+- in czech republic so it looks like good card for that money, or not ?

hold on, do you already have a 3870x2 and you want to crossfire them?

eitherway, it's not a good card for the money.

No I dont have that card yet

5850 price may drop considerably.

Can you find stock of 4890 or 4870 for cheap?

All those would be better than the 3870x2. I had one and changed to a 4870 512mb a couple years ago and was pleased with the change. . .

I wouldn't crossfire them, I don't think you'll get much improvement using quad xfire.

5850 is high, 4870 is about 2k ... so still twice more than 3870x2 , do you think that is 3870x2 good deal for this price (1k) ?

Well to me it looks cheap (if I got the concersion right   ). But it's a pretty old card so I really dont know. How about a GTX 460 or maybe 5770, don't know, putting two old GPU's in CF doesnt seem like a good decision in my opinion.

From what I read 3870X2 in CF have some problems, like not being able to turn AA on etc.

Flisker if your budget is really only 1000 Koruna (~$50) then I guess your best off doing what you already decided. Just know that you are getting an older card (two of them) that won't support some newer technologies (like the latest directx). You'll be able to play most all games for a while in the future though.

If you can go for a little more money, get a single 6850 right now and then in the future buy another one. The one 6850 will be way better than two 3870s, if you can afford it.

Ok, thank you for help.

You are welcome.

Btw what about 8800GTS 640/512, 8800GT or 9800GTX are these better option than 3870x2 ? All these cards are nearly in same price range. (btw I have mobo with CF support)

From these ^^^ the 9800GTX is the most powerfull. But the 3870X2 in CF should be more powerfull.

BTW you should chech if your second PCI-E x16 runs at x16(not likely) x8 or at x4. Because if it runs at x4 it is not going to be great for CF.

Sadly second PCI-E is 4x but it should be "only" about 20-30% loss in performance of second card if I am right.

Might not be worth the crossfire then... your call though.

Also your Chipset is probably not he best, for crossfire the 790FX ( Nowadays I think it's the 890FX, but your Mobo is probably older) is the best, so if you chipset is say a 780 it will also decrease performance.

Maybe you should go for the 9800GTX and don't worry about Drivers, Game bugs etc. in my humble opinion  

My mobo is ASUS P5K/EPU, I am still not sure what am I going to buy  

what is the maximum you want to spend, or can spend?

also what do you plan to play on your computer?

I reccomend the 9800GTX you don't look like a very hardcore gamer and I think you will like it's performance and it looks like the simplest option since it fits your tight budget.

By the way what's your resolution ?

up to 1.5k for now. what games ? it depends on how good graphic will I manage to get  

my res is 1280x1024 on 17" lcd

At this resolution I think that the 9800GTX will be enoug for enjoyable gameplay.

http://benchmarkreviews.com/index.php?option=com_conten...

http://benchmarkreviews.com/index.php?
option=com_content&task=view&id=154&Itemid=1&limit=1&limitstart=9

http://www.tweaktown.com/articles/1356/nvidia_geforce_9...

At your resolutiun and medium detail Crysys should run 50+ FPS which is great gameplay  

Ok, thank you both for help i will try to fing 9800GTX for good price now  

You are welcome.

Good luck  

Hope you find one that fits your budget  

3870 cf should be around one hd4850/5750 , on the nvidia side its about 9800gtx/gts250 and bordering gts 450

if the board supports it and its cheap its not a bad way to go
i'd prefer a single card over a crossfire/sli solution but if the 3870's are cheaper than any of the above mentioned cards then go for it

i am curious though as a 5670 > a 3870 what 5670's go for as xfire 5670 will be faster, more efficient and scale better in crossfire