Now, this graphics card is getting on a bit now, and I may have had it for 2 or 3 years but it still never fails to impress me.
The HD 4850 from ATI will allow you to play most new releases on max or near max settings (depending on your CPU), which is extremely impressive for it's low price. Other graphics cards from nVidia, with similar performance capabilities may cost you up to £100 more, which really proves that ATI is the way to go.
The card also has 512MB of video RAM, maybe a bad point for those who game at insane resolutions or use more than 1 monitor, which I do neither of. I game at 1080p (1920x1080) which to be honest, IS a quite high resolution and this card doesn't even break a sweat. In other words, 512MB is enough for most people, and if that still isn't enough, there is also a 1GB version available for very little more.
Connectivity wise, this card does have one shortfall which is that it doesn't have a HDMI port. This means you won't be able to connect it directly to a TV using it, but you don't need it anyway as most HDTVs also have a PC port which allows you to connect a VGA cable from the graphics card (using the included DVI-VGA converter as this card does not have any VGA ports). Also, 1080p TVs still use a resolution of 1920x1080 which means you can be gaming in 1080p through your TV, just like you had a PS3 or Xbox 360.
This coupled with a 360 controller for your PC (read my review for it for more info) will make it feel like you are playing Xbox 360 games through your TV (also with the lower price of PC games it's a win-win situation).
A second disadvantage however is that this card does not support DirectX11, which most of the new games include, so if you are so adamant about having DirectX11, a HD5750/5770 would be a more suitable choice as these cards also feature superior performance but for a more expensive price tag.
Currently this card is good enough for playing new games - some, if I'm lucky, on maximium settings, others I find myself turning down some things like shadows and aliasing.
The card itself hums a bit once it's been in-game for a while, though with my headphones on I hardly hear it. Like most gaphics cards it gets a little hot too, though it doesn't cause any problems.
With some settings tweaks games like Assassin's Creed 2, Battlefield BC2 and Just Cause 2 all run at 30fps+. Some games like Bioshock and Mass Effect 2 run great on maximum though.
Moving away from the graphics side of things the card boasts AVIVO video processing which comes in really handy when films are dark since my TFT's backlight isn't that great. I can boost the colours, contrast, brightness, colour vibrancy and whatnot. It all makes films look that much nicer and like I'm watching on a more expensive screen :P.
I've had no problems with using two monitors with the card either. However, Window's aero theme runs a smidge slower with two monitors enabled.
Lastly, whilst this is a great card, if you're going for a new graphics card I'd advise going for the current HD5000 series (which support DirectX 11) unless you're getting a good deal on this card or something. Plus there's the HD6000 series shipping at the end of this year.
I have this graphics card in my setup and theres a few things id like to say about it,
The first thing is that it is Extremely good value for money (got mine for about £130)
The custom fan on it is very good although when you get the card i reccomend installing the latest version of catalyst so you can up the fan speed from a low 30% up to 90% (still silent compared to my antec tri cool fans) but do make sure you turn the fan speed up as the factory standard is terribly low
If this is the version with the heatsink (it shouldnt be but you may not always know) i reccomend getting extra cooling for it as the heatsink on the 4000 cards is terrible.
This card itself has performed very well for me playing games like fallout 3 on 1280 x 1024 resolution with max settings and 4 times AA without any decrease in performance,
And because its by ATI and uses catalyst it is very easy to overclock