Graphics card supported or not for my system?

PCI 2.1 is backwards compatible with version 2.0. Not to worry.

Your PSU is fine for running either of the cards you mention.

thanks for the info. can you please tell me which one is the better among the following. gts 250(2 gb) vs radeon 6870(1gb)? recently I have gts 250(2 gb). Want to upgrade to radeon 6870 1gb.. 2gb is not available  

2GB of RAM on a video card is not absolutely essential unless you are playing on an ultra high resolution display (around 2560x1600 resolution), or doing multimonitor gaming. The GTS 250 isn't powerful enough to use more than 1GB of memory anyway. The 6870 is a big jump in overall performance over the GTS 250 2GB, even with only half the RAM.

The 6870 is also not quite powerful enough to really use more than 1GB of RAM, though there may be a few scenarios where it can use more than 1GB with some games that have high res texture packs. The vast majority of the time though, the 6870 will run out of steam before it goes beyond 1GB of RAM. As such, I wouldn't really worry about not being able to get a 2GB card. If you really want a 2GB card, look at some of the newer cards out there, like the Radeon HD 7850, they come with 2GB of RAM as a standard feature.

actually I dont have enough budget to purchase 7 series. Can you please which one should I go? options are - hd 6870 or 6950?

The 6950 is a bit faster than the 6870, approximately 10% faster. Under some circumstances the 6950 is actually is fast enough to benefit from 2GB of RAM, but that is mostly only at 2560x1600 on certain specific games. The 1GB version is still a good card. I would say get the best that you can afford, especially if you plan on playing some of the really demanding games out there, like Crysis, Battlefield 3, Witcher 2, or Metro 2033. Those games require a lot of GPU horsepower. Other titles tend to be less demanding, and will run just as well with a 6870 as they would with a 6950.

and what about gtx 560 ti or gtx 570? are they better than hd 6870/6950?

The 560Ti performs similarly to the 6950, with the 6950 pulling ahead in some games. The GTX 570 performs similarly to the Radeon HD 6970, and a bit faster than the new 7850 when the 7850 operates at stock clocks. If you can afford a GTX 570, I would think you could look at the 7850 too, or is the particular 570 you are looking at a used or refurbished card?

It will be no problem with your CPU and PSU !! its fully compatible !

I have MSI785G E53 motherboard with one pci 2.0 slot , amd phenom ii X4 quad core processor and PSU 550 watt.. So, gtx 570, radeon 6950 will support for it?

You're fine for either of those cards. PCI Express compatibility is only a problem with some of the really old PCI-E 1.0 boards when you use a PCI-E 2.1 or 3.0 card.

I'm not going to repeat what everyone said but 2.1 is backwards capable....oh wait ......whoops

Hi, I have checked this website http://www.club-3d.com/index.php/products/reader.en/pro... .

Its saying that min power supply required is 600 watt.. but I have only 550 watt and Two 6 pin PCI Express supplementary power connector..what does it mean?

You should be OK if you have a quality power supply. Those wattage numbers are just guidelines.

What brand and model of power supply do you have?

http://www.coolermaster.in/product.php?product_id=5906 .. This one I owned. http://www.club-3d.com/index.php/p [...] x-570.html , in this website its wrote that Two 6 pin PCI Express supplementary power connector needed. so, can I able to set up gtx 570 or 6970?

You should be able to set up a single 570 or 6970 without problems.

Oh yeah thats plenty of power for pretty much any single graphics card

ok thanks. But I have two questions buddy..

1. As per http://www.club-3d.com/index.php/products/reader.en/pro... this , Minimum of 550 Watt or greater system power supply (with a minimum +12V current rating of 38Amps) required. Now my PSU has 600 watt but current rating of total 36   which is below per requirement. So, thats will be an issue?

2. And as per http://www.coolermaster.in/product.php?product_id=5906 there are no 8 pin but according to http://www.club-3d.com/index.php/products/reader.en/pro... this, one 8 pin is required.. so how will I be able to set up hd 6970 ?

"Minimum of 550 Watt or greater system power supply (with a minimum +12V current rating of 38Amps) with two supplementary 6-pins PCI Express power connectors"

You are quite right about the amperage and being 2 amps shy. As for the power connector, that's not a problem, the CM has a 6+2 connector, which is just fine for that card.

That being said though, you are power shy and will need to get a different PSU if you really are set on using that card. My humblest apologies for not having investigated that further before making my recommendation.