Radeon HD 4870 1GB vs Radeon HD 4870 512MB

Intro

Compare those specs to the Radeon HD 4870 512MB, which comes with GPU core speed of 750 MHz, and 512 MB of GDDR5 memory set to run at 900 MHz through a 256-bit bus. It also is comprised of 800(160x5) Stream Processors, 40 Texture Address Units, and 16 ROPs.

Battlefield Bad Company 2

Settings:	High Quality
AA:	4x
AF:	8x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 1GB		33 FPS
Radeon HD 4870 512MB		20 FPS
	Difference: 13 FPS (65%)

F.E.A.R. 2

Settings:	Maximum Quality
AA:	4x
AF:	8x
Resolution:	1920x1200
Test Machine:	Unknown (Source)

Radeon HD 4870 1GB		78 FPS
Radeon HD 4870 512MB		78 FPS
	Difference: 0 FPS (0%)

Fallout 3

Settings:	Very High Quality
AA:	8x
AF:	16x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 1GB		58 FPS
Radeon HD 4870 512MB		51 FPS
	Difference: 7 FPS (14%)

Fallout 3

Settings:	Very High Quality
AA:	4x
AF:	8x
Resolution:	1680x1050
Test Machine:	Tom's Hardware Charts Test Rig (Source)

Radeon HD 4870 1GB		74 FPS
Radeon HD 4870 512MB		71 FPS
	Difference: 3 FPS (4%)

Left4Dead

Settings:	Very High Quality
AA:	8x
AF:	16x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 1GB		74 FPS
Radeon HD 4870 512MB		72 FPS
	Difference: 2 FPS (3%)

Left4Dead

Settings:	Very High Quality
AA:	4x
AF:	8x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Charts Test Rig (Source)

Radeon HD 4870 1GB		80 FPS
Radeon HD 4870 512MB		78 FPS
	Difference: 2 FPS (3%)

Left4Dead 2

Settings:	Very High
AA:	8x
AF:	16x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 1GB		80 FPS
Radeon HD 4870 512MB		77 FPS
	Difference: 3 FPS (4%)

Mass Effect 2

Settings:	Maximum Quality
AA:	none
AF:	8x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 1GB		98 FPS
Radeon HD 4870 512MB		96 FPS
	Difference: 2 FPS (2%)

Supreme Commander 2

Settings:	High
AA:	8x
AF:	16x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 1GB		57 FPS
Radeon HD 4870 512MB		55 FPS
	Difference: 2 FPS (4%)

Tom Clancy's Endwar

Settings:	High Quality
AA:	4x
AF:	8x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 1GB		30 FPS
Radeon HD 4870 512MB		30 FPS
	Difference: 0 FPS (0%)

Tom Clancy's H.A.W.X

Settings:	High Quality
AA:	4x
AF:	8x
Resolution:	1680x1050
Test Machine:	Tom's Hardware Charts Test Rig (Source)

Radeon HD 4870 1GB		36 FPS
Radeon HD 4870 512MB		36 FPS
	Difference: 0 FPS (0%)

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Radeon HD 4870 1GB wins

(Based entirely on the benchmarks listed above)

When combining all game benchmark scores on this page together, the Radeon HD 4870 1GB wins overall, by 34 FPS. Please note that we do not have the results of every benchmark ever done for these cards, so the results may differ wildly in different games.

Radeon HD 4870 1GB		698 FPS
Radeon HD 4870 512MB		664 FPS
	Difference: 34 FPS (5%)

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

Both cards have exactly the same memory bandwidth, so in theory they should perform the same. (explain)

Texel Rate

Both cards have the exact same texel fill rate, so in theory they should perform equally good at at AF. (explain)

Pixel Rate

Both cards have exactly the same pixel fill rate, so theoretically 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: Memory bandwidth is the largest amount of information (counted in MB per second) that can be transferred past the external memory interface in one second. It's calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's 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 can be applied per second. This figure is calculated 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 card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card 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 colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.