Scan's TekSpek

Our Aim
To provide you with an overview on New And existing technologies, hopefully helping you understand the changes in the technology. Together with the overviews we hope to bring topical issues to light from a series of independent reviewers saving you the time And hassle of fact finding over the web.

We will over time provide you with quality content which you can browse and subscribe to at your leisure.

TekSpek GPU - Graphics
AMD Radeon HD 7870 and HD 7850

AMD Radeon HD 7870 and HD 7850

Date issued:

AMD is completing a transition to Radeon HD 7000-series graphics cards with the announcement of the Radeon HD 7870 2GB and Radeon HD 7850 2GB graphics cards today. It is expected that both cards will be made available via the usual partners - Sapphire, XFX, PowerColor, ASUS, MSI, et al - from week beginning March 19, 2012.

Radeon HD 7870 and HD 7850 are high-end graphics cards designed for the enthusiast. Due to be priced at around £270 and £190, respectively, they can be considered direct replacements for the Radeon HD 6970 and HD 6950 parts that have been available for the past 15 months or so. Looking toward the competition from the NVIDIA side, the two are set to compete with the GeForce GTX 580/570 and GeForce GTX 560 Ti and Ti 448 models. This TekSpek is of interest to anyone considering spending £200 or so on a graphics card in the next two months.

The Radeon HD 7870/50, codenamed Pitcairn, are based on exactly the same technology used to power the recently-released Radeon HD 7970 3GB and HD 7950 3GB super-high-end parts. This means they are strong on performance and features, with AMD placing particular emphasis on making them energy efficient, that is, drawing the least amount of power possible.

How they stack up

GPU Radeon HD 7970
Radeon HD 7950
Radeon HD 7870
Radeon HD 7850
Codename Tahiti XT Tahiti Pro Pitcairn XT Pitcairn Pro
DX API 11.1 11.1 11.1 11.1
Architecture GCN GCN GCN GCN
Process 28nm 28nm 28nm 28nm
Transistors 4.3bn 4.3bn 2.8bn 2.8bn
Die Size 352mm² 352mm² 212mm² 212mm²
Processors 2,048 1,792 1,280 1,024
Default memory 3GB 3GB 2GB 2GB
Compute units 32 28 20 16
Texture Units 128 112 80 64
ROP Units 32 32 32 32
GPU Clock (MHz) 925 800 1,000 860
Shader Clock (MHz) 925 800 1,000 860
GFLOPS 3,789 2,867 2,560 1,761
Memory Clock (MHz) 5,500 5,000 4,800 4,800
Memory Bus (bits) 384 384 256 256
Max bandwidth (GB/s) 264 240 153.6 153.6
Power Connectors 8+6 6+6 6+6 6-pin
TDP (watts) 250 200 175 130
GFLOPS per watt 15.15 14.34 14.63 13.55
CrossFire Support 4-way 4-way 2-way 2-way
Release MSRP $549 $449 $349 $249

This table shows how they stack up against the two faster cards from AMD's current stable of high-end GPUs. Understandably, to achieve a lower price point AMD cuts down on the architecture, especially with respect to memory bandwidth. This means the HD 7870/50 may be significantly slower than their £350-plus brethren if the image-quality settings and resolution - two parameters that need memory bandwidth - are turned all the way up.

Radeon HD 7870 2GB

The faster of the new duo is the Radeon HD 7870, pictured above. Independent testing shows its performance to be between NVIDIA GeForce GTX 580 and GTX 570 levels and somewhat faster than the Radeon HD 6970. Considering the cutting-edge technology, broad feature-set, especially with respect to multimedia functions, it is, right now, the best graphics card under £300.

What's more, Radeon HD 7000-series graphics cards have the propensity to overclock well - AMD has set the frequencies conservatively, which is altogether impressive given the 1,000MHz core clock on this model.

It is expected that AMD's retail partners will simply use the cooling solutions already implemented on special-edition Radeon HD 6970/50 models for this GPU, so expect to see near-silent cards from a complete roster of partners. Also, going hand in hand with the cooling, expect to see factory-overclocked cards from all partners.

Radeon HD 7850 2GB

Meanwhile, Radeon HD 7850 is a considerably less power-hungry card than its bigger brother. Indeed, AMD reckons it will be possible for add-in board partners to release custom-designed cards that are only 7.5in long, meaning they can fit into a wide range of chassis. And the fact that it uses just one six-pin PCIe connector - used to power the board from the power supply - bodes well for SCAN shoppers who have medium-wattage power supplies in the 400-600W range.

Just like the Radeon HD 7870, a second card can be connected to form two-way CrossFire rendering. This can push up the speed to almost 2x a single card's for some of today's most popular games, according to AMD's internal testing and figures.

Radeon HD 7850 also shares the large 2GB GDDR5 framebuffer as the HD 7870 card, enabling it to run games smoothly once high- and ultra-high quality settings are chosen. It is good enough to provide a smooth games-playing experience at a full-HD, 1,920x1,080 resolution that's common on many of the TFT monitors used by gamers, and it benchmarks at about the same speed as NVIDIA's GeForce GTX 560 Ti 448 card and, crucially, faster than AMD's last-generation HD 6950.


AMD's release of two high-end cards known as Radeon HD 7870 2GB and Radeon HD 7850 2GB cements its position as provider of the best enthusiast-orientated GPUs. The new duo are to replace existing Radeon HD 6000-series cards such as the HD 6970 and HD 6950, so you may find them on offer in the coming weeks - keep your eyes peeled for the SCAN Today Only page.

Fast, power efficient and boasting a fulsome feature-set, the Radeon HD 7800-class of graphics cards should very definitely be on your shortlist if you require a top-quality card with the latest technology. SCAN is sure to list a full selection of cards from practically all of AMD's partners in the coming days.

One word of warning however, as arch-rival NVIDIA is slated to release its latest family of graphics cards, codenamed Kepler, in April 2012. No one yet knows whether AMD or NVIDIA will have the bragging rights in a couple of months' time, though the fierce competition between the two companies is sure to benefit you, the SCAN shopper.