Something about ATI Radeon 4870 X2

[Lucky Luke]

Guys, for those of you who are interested more on updates on the ATI Radeon 4870 X2, you can have a look at this link below :

http://www.hardwarezone.com.sg/articles/view.php?cid=3&id=2653

I am now wondering...currently NVIDIA's latest single GPU card is the 280 GTX. Would somebody please explain which is the most important parameter that considers a GPU to be the MOST powerful? Is it the amount of memory? The Memory clock speed? There are so many of these parameters you can find there. Thanks for your time :)

[hdantman]

Lucky,

1.) Pixel fill rate (the number of pixels the card can draw per second)
2.) Rasterization rate (the ability to wireframe render an image using vertices/triangles)
3.) FLOPS (FLoating Point Operations Per Second, which is the amount of calculations performed, such as placing pixels/wireframe connections within a given plane)
4.) All of the above are determined by memory bandwidth, which is the speed at which the onboard RAM (the speed/clock frequency of the RAM plays it's part here) can communicate with the onboard processor/GPU (processor clock speed plays it's part here).
5.) Vertex and fragment shaders (pipelines which make up the processor,) within the GPU contribute (or should I say determine) the ability of the GPU to quickly render the image (rasterize) and add volumentric and 3D effects(color and spatialize the image), so the number of pipelines largely determines the speed/functionality of the board, as it precedes the pixel fill. I should note here that there have been recent shifts (improvements) from fixed pipelines to programmable pipelines and now to unified pipelines that have altogether changed the way this is performed, but this is the basic idea. Today's GPUs are actually comprised of many processor pipelines or cores performing calculations in parallel, so there is no traditional individual cpu, such an intel pentium 4. The architecture of CPUs and GPUs is starting to merge, which is why we'll see huge innovation in the next five years or so in both markets (CPU and GPU).
6.) The framebuffer (amount of RAM onboard used to store pre-rendered images for use in later frames) must be adequate to maintain good framerates, but this is determined by the texture sizes used by the games/applications at hand, and the number/type of onboard features being used, such as FSAA (full-screen anti-aliasing). Most games in use today use less than 512MB for this, but using uncompressed textures can result in a better visual experience, so card manufacturers are going to increase the framebuffers incrimentally as time goes on.
7.) Finally, the interface through which the CPU and the GPU communicates must be adequate to support the requests of the graphics board for information, which is why PCI-express 2.0 x16 is used (higher bandwidth than AGP or PCI) in the newest cards. This is not really a huge concern right now, because this standard is implimented to future-proof motherboards, as the specification provides more than adequate bandwidth for years of innovation in graphics technologies to come. I should add that graphics board manufacturers and software designers have been working together recently to move previous CPU functions such as physics processing over to the GPU. We see this in technologies such as CUDA which manifests in the forms of PhysX and Havok.

Last, but certainly not least, drivers for the cards are probably the single most important factor that determines whether or not a given card will play a game well. A great card paired with poor drivers will perform well below its capability, and perhaps well below a lesser card with good drivers. That's why it's important that video hardware manufacturers work side by side with game development teams to develop games and good drivers.


Pixel fill rate, and texture fill rate are the two easy tell-tale signs of a better card. You can look them up and compare them for each card using the compare page on this site. A higher number will be bolded, and will indicate probable superior performance when it comes to games.

I hope this provides an answer for you that is less than comprehensive, but more than accurate to the point.

[Lucky Luke]

Wow, thanks for the very detailed explaination,Hdantman. Really appreciate that. I'll read n re-read again n again to familiarise to these jargons. Ok,the texture n pixel fillrate's the most important ones. I'll pay a closer attention for these 2. ;-)

[McArthur]

Of course, fillrate isn't the only factor.

The GTX280's fillrate is far lower than the 9800GX2, but it still beats the 9800GX2

Drivers play an important role in performance too.

[Lucky Luke]

Hm,yeah you're rite McArthur. Driver's important too. But,to me..having a correct driver shouldn't be a problem coz we can always download from the web for latest driver regularly. But,thnx anyway for your input.:-)

[Radiator]

In most cases , the GX2 beats the GTX280.. only at high resolutions where the GX2's amount of vRAM is insufficient , the GTX280 beats it .
As for ATi cards , the drivers are prettymuch half the card ... they play a much larger role because of ATi's complex superscalar architecture , compared to nVidia's simpler scalar architecture .

What's the most important parameter ... the combination of them + the architecture itself , there is no certain parameter , that would make it tons faster by just increasing the amount of that certain bit of hardware on the chip .

[hdantman]

Well said, Radiator. Hence, my long answer.

[Lucky Luke]

Uhm,guys. Talking abt the GPU driver as 1 of the most important parameter,how do I ensure that the driver is the best for the card? Is it
enough by just downloading for the latest driver frm the net? Thnx.

[Radiator]

If you have the current generation of video cards (or the previous generation), then yeah ... I for one haven't updated my drivers since the Catalyst 7.6 , I believe

[hdantman]

What Radiator said,

but also, you can check forums like these, and google to see what luck people have had with other sets of drivers using your card.

Sometimes the newest ones aren't always the best. Usually, they are.

[Radiator]

Considering you are getting a HD 4870 X2 , definitely get the Catalyst 8.8 beta drivers .
But as a couple of reviews have already stated , theres absolutely no point whatsoever in getting a HD 4870 X2 ( or a GTX280 ) for low resolutions , like that .
Save yourself some money , and get a HD 4870 .

[hdantman]

No kidding. Especially since the prices for these cards are about to drop $100.