Radeon HD 4870 512MB vs Radeon R9 270X

Intro

Compare those specifications to the Radeon R9 270X, which has a core clock frequency of 1000 MHz and a GDDR5 memory frequency of 1400 MHz. It also uses a 256-bit bus, and makes use of a 28 nm design. It is comprised of 1280 SPUs, 80 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
Radeon R9 270X		180 Watts
	Difference: 30 Watts (20%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 270X is 56% quicker than the Radeon HD 4870 512MB overall, due to its higher data rate. (explain)

Radeon R9 270X		179200 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 64000 (56%)

Texel Rate

The Radeon R9 270X is quite a bit (more or less 167%) faster with regards to texture filtering than the Radeon HD 4870 512MB. (explain)

Radeon R9 270X		80000 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 50000 (167%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon R9 270X is the winner, and very much so. (explain)

Radeon R9 270X		32000 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 20000 (167%)

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 largest amount of data (in units of megabytes per second) that can be moved over the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics 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 maximum amount of pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the card's 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 rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.