Radeon HD 4890 1GB vs Radeon R7 250X 2GB

Intro

Compare all of that to the Radeon R7 250X 2GB, which comes with a clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also uses a 128-bit memory bus, and uses a 28 nm design. It features 640 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R7 250X 2GB		95 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 95 Watts (100%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4890 1GB will be 73% faster than the Radeon R7 250X 2GB overall, due to its higher bandwidth. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon R7 250X 2GB		72000 MB/sec
	Difference: 52800 (73%)

Texel Rate

Both cards have the exact same texel rate, so theoretically they should be equally good at at anisotropic filtering. (explain)

Pixel Rate

Both cards have exactly the same pixel fill rate, so in theory they should perform equally good at at AA, and be able to handle the same screen resolutions. (explain)

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 data (measured in MB per second) that can be moved past the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. If the card has DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster 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 number of texture map elements (texels) that are processed in one second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.