GeForce GTS 250 512MB vs Radeon HD 4770

Intro

Compare those specifications to the Radeon HD 4770, which features a clock frequency of 750 MHz and a GDDR5 memory frequency of 800 MHz. It also makes use of a 128-bit memory bus, and makes use of a 40 nm design. It is comprised of 640(128x5) SPUs, 32 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
GeForce GTS 250 512MB		145 Watts
	Difference: 65 Watts (81%)

Memory Bandwidth

The GeForce GTS 250 512MB should theoretically perform much faster than the Radeon HD 4770 overall. (explain)

GeForce GTS 250 512MB		70400 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 19200 (38%)

Texel Rate

The GeForce GTS 250 512MB will be a lot (approximately 97%) faster with regards to anisotropic filtering than the Radeon HD 4770. (explain)

GeForce GTS 250 512MB		47232 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 23232 (97%)

Pixel Rate

The Radeon HD 4770 is just a bit (about 2%) more effective at anti-aliasing than the GeForce GTS 250 512MB, and will be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 4770		12000 Mpixels/sec
GeForce GTS 250 512MB		11808 Mpixels/sec
	Difference: 192 (2%)

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: Memory bandwidth is the maximum amount of data (counted in megabytes per second) that can be transported across the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.