GeForce GTS 250 1GB vs Radeon HD 4850 X2 1GB

Intro

Compare those specifications to the Radeon HD 4850 X2 1GB, which uses a 55 nm design. ATi has clocked the core frequency at 625 MHz. The GDDR3 RAM is set to run at a frequency of 993 MHz on this card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTS 250 1GB		145 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 105 Watts (72%)

Memory Bandwidth

In theory, the Radeon HD 4850 X2 1GB is 81% faster than the GeForce GTS 250 1GB overall, because of its greater data rate. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
GeForce GTS 250 1GB		70400 MB/sec
	Difference: 56704 (81%)

Texel Rate

The Radeon HD 4850 X2 1GB will be just a bit (about 6%) faster with regards to anisotropic filtering than the GeForce GTS 250 1GB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
GeForce GTS 250 1GB		47232 Mtexels/sec
	Difference: 2768 (6%)

Pixel Rate

The Radeon HD 4850 X2 1GB will be much (about 69%) faster with regards to anti-aliasing than the GeForce GTS 250 1GB, and also capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
GeForce GTS 250 1GB		11808 Mpixels/sec
	Difference: 8192 (69%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of information (in units of MB per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.