AMD's Radeon HD 2900 XT Reviewed

J. Dzhugashvili writes "The folks at The Tech Report have whipped up a detailed expose of the new AMD Radeon HD 2900 XT graphics card's architecture and features, with plenty of benchmarks. While the card dazzles with 320 stream processors, a 512-bit memory bus, and oodles of memory bandwidth, its performance and power consumption seem disappointing in the face of Nvidia's six-month-old GeForce 8800 graphics cards."

Comments

A number more reviews

[bad_fx]

As usual Anandtech is extremely thorough: http://www.anandtech.com/video/showdoc.aspx?i=2988 &p=26

[H]ardocp's take: http://enthusiast.hardocp.com/article.html?art=MTM 0MSwxLCxoZW50aHVzaWFzdA==

techPowerUp (Warning, streaming video at the start >.>): http://www.techpowerup.com/reviews/ATI/HD_2900_XT/

The Inquirers expected vapid coverage: http://www.theinquirer.net/default.aspx?article=39 580

I think I'll wait for more ATI drivers and some DX10 games before calling this one... Looks a little underwhelming at the moment though. I'm not regreting my 8800GTX purchase yet. ;)

Folding@home performance

[Anonymous Coward]

This board has still more "crunching" performance than older generations, but the power usage is insane:
http://forum.folding-community.org/fpost185371.htm l#185371
http://folding.stanford.edu/FAQ-ATI.html

idle & load power ratings are scary

[Adult film producer]

Idle
----
Radeon 2900XT - 183
GeForce 8800 Ultra - 192
GeForce 8800 GTX SLI - 296
Radeon 2900XT Crossfire - 317


Full Load
---------
Radeon 2900XT - 312
GeForce 8800 Ultra - 315
GeForce 8800 GTX SLI - 443
Radeon 2900XT Crossfire - 490


This could get very expensive for people that leave their computers running 24/7.

Re:idle & load power ratings are scary

[bad_fx]

Just a note, that is for the entire system, rather than just the graphics card. Still high compared to older generations. Just thought I'd point it out, since it may not be clear.

Re:idle & load power ratings are scary

[tknd]

Power supply manufacturers typically pick a number close to the maximum possible consumption the unit can provide utilizing the maximum across all the different voltages it provides. So when you look at the sticker on the PSU, it will show you the maximum amps per each voltage. You take all of these numbers, multiply the voltage by the amps to get the watts (watts = volts * amps). Then add all of those numbers together to get the total maximum power the PSU can provide. That number should be fairly close to what the manufacturer advertises their PSU as.

The problem with the components in the computer is that they utilize different voltages. So what eventually happens is components require more current on a certain voltage than the PSU can offer at that voltage, however, the other voltages aren't maxed out. That's why people typically have problems with PSUs because they didn't read the sticker and compare the maximum current per each voltage compared to their actual needs. That's also why if you're smart, you can actually get by on a PSU rated at a lower total maximum wattage than a higher rated one (that may just load up on the lower voltages but leave the +12V line crappy to inflate the total maximum power number).

The final bit of information is that many reviewers are reviewing systems by total system power draw at the plug. The biggest factor that is altering this number is the PSU's efficiency rating. There are some really cheap PSUs that advertise high numbers but come with really bad efficiencies (in the 60% to 50% efficiency range). The efficiency of the PSU typically isn't given by many manufacturers. So what all this means is while the total system power consumption is 430watts at the plug, the components may only be eating 300 watts and the PSU is only 70% efficient. If you were to buy a PSU that was 80% efficient while providing 300watts, then your total system power at the plug would be about 376watts. But since many manufacturers don't provide the efficiency rating, you have to rely on data from the internet and more knowledgeable reviewers.

Re:Let's hope

[Psiven]

You can do pretty well estimating your performance if you have a general understanding of how your components work together.

First measure FPS in your favorite app at the lowest resolution. That's the measure of your CPU bottleneck. No matter how nice of a GPU you buy, you'll never get higher FPS than that.

Memory is one of those things you can never have enough. Just don't worry about the bandwidth too much. Your only going to squeeze out just a few frames per second with top of the line RAM. Just watch to see if your comp is hitting the hard drive much and consider more if it is.

Most new games are still GPU limited and this is where you want to focus your attention. Look for benchmarks at resolutions you play at. This is a good baseline of what to expect. Anything over 60fps avg I tend to be happy with, but you may want consider the minimum too. Right now the only benchmarks I've really been interested in are of Rainbow Six: Vegas. It uses the Unreal 3 Engine, and a lot of games are coming out that are going to be using it too. Other benchmarks might be important to you as well, but they tend to rank in the hundreds and so you know performance won't be an issue.

Re:Let's hope

[19thNervousBreakdown]

This comes up every single time, so forgive me if I'm not as polite about it as I could be.

The human eye sees ~25-30fps, true, but it does not sample the same way your monitor outputs it. The human eye refreshes at that rate, which means anything that's seen for less than that amount of time leaves a partial imprint. Thus, the motion blur you see when something, even in real life, goes by really fast. Since the monitor is outputting static frames, you don't get that partial imprint, and it looks choppy. Television, on the other hand, does pick up the motion blur, because of the way the cameras work. There are a number of studies showing that we benefit from higher FPS, up to and over 100 sometimes.

Also, there's really no such thing as 32-bit color. I suppose you could put a different number of bits for RGB, and many schemes do, but the 32-bit you're thinking about is RGBA. 24-bit is the exact same thing, without the alpha channel, and we also benefit from far more colors than current hardware outputs, because the current 16.7m colors that are output don't account for much luminosity, and for plenty of other reasons I don't care to look up right now.

When you try to stick your hand through the monitor and pick up a Coke, or catch a running kitten, that's when you can say we've got enough. Until then, please try to at least understand the subject you're discussing, and not try to come off as authoritative when you don't even know what 32-bit color means.