GeForce GTS 250 512MB vs Radeon HD 3870 512MB

Intro

Compare those specs to the Radeon HD 3870 512MB, which has a clock speed of 775 MHz and a GDDR3 memory frequency of 900 MHz. It also uses a 256-bit memory bus, and makes use of a 55 nm design. It is made up of 320(64x5) SPUs, 16 TAUs, and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
GeForce GTS 250 512MB		145 Watts
	Difference: 39 Watts (37%)

Memory Bandwidth

In theory, the GeForce GTS 250 512MB should perform much faster than the Radeon HD 3870 512MB overall. (explain)

GeForce GTS 250 512MB		70400 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 12800 (22%)

Texel Rate

The GeForce GTS 250 512MB is a lot (about 281%) more effective at anisotropic filtering than the Radeon HD 3870 512MB. (explain)

GeForce GTS 250 512MB		47232 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 34832 (281%)

Pixel Rate

The Radeon HD 3870 512MB will be just a bit (about 5%) better at full screen anti-aliasing than the GeForce GTS 250 512MB, and capable of handling higher resolutions more effectively. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
GeForce GTS 250 512MB		11808 Mpixels/sec
	Difference: 592 (5%)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the largest amount of information (in units of MB per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the interface width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. 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 rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.