Radeon HD 4870 1GB vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which features GPU core speed of 1000 MHz, and 1024 MB of GDDR5 memory running at 1125 MHz through a 128-bit bus. It also is made up of 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon HD 4870 1GB		150 Watts
	Difference: 70 Watts (88%)

Memory Bandwidth

Theoretically, the Radeon HD 4870 1GB should perform a lot faster than the Radeon HD 7770 overall. (explain)

Radeon HD 4870 1GB		115200 MB/sec
Radeon HD 7770		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon HD 7770 should be much (approximately 33%) better at texture filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 10000 (33%)

Pixel Rate

The Radeon HD 7770 should be quite a bit (approximately 33%) more effective at AA than the Radeon HD 4870 1GB, and also able to handle higher screen resolutions better. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 4000 (33%)

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 maximum amount of data (measured in megabytes per second) that can be transferred over the external memory interface in one second. It's worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the clock 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 output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.