Introduction

Towards late-November last year, AMD made a halfhearted attempt at launching a new performance-segment GPU that strikes a price-point right in between the Radeon HD 7870 GHz Edition and the Radeon HD 7950, and that's putting it mildly. There was confusion over specifications and name until the very last minute. AMD finally decided not to make a reference-design card which left the decision to its partners, most of whom decided against releasing the SKU so as not to disturb their swelling HD 7870 GHz Edition and HD 7950 inventories. To make matters worse, AMD chose the brilliant SKU name of "Radeon HD 7870".



Amongst the AMD board partners that opted to make cards based on this chip, which has been codenamed "Tahiti LE," are Sapphire and those that rely on contract manufacturer TUL Corporation. These board partners include Club3D, PowerColor, and VTX3D, and the latter two are even owned by TUL. Today, we have with us VTX3D's contraption called the HD 7870 Black.



AMD's new GPU is called "Tahiti LE" even though it's a part of the Radeon HD 7800 series, because it is derived off the same 3.5 billion-transistor "Tahiti" silicon that goes into making all Radeon HD 7900 series products, not the "Pitcairn" silicon that goes into making the HD 7870 GHz Edition and HD 7850. The new SKU drops the "GHz Edition" moniker by featuring lower clock speeds than the HD 7870 GHz Edition, but it makes up for that with more pixel-crunching muscle.

The HD 7870 "Tahiti LE" is carved out of the Tahiti silicon by disabling a fourth of its Graphics CoreNext clusters, which results in a stream processor count of 1,536, a texture memory unit (TMU) count of 96, and a raster operations processor (ROP) count of 32. The memory bus width has been reduced by a third; now, it is 256-bit wide and holds 2 GB of memory. The new chip features PowerTune with Boost: a dynamic core overclocking equivalent to NVIDIA's GPU Boost. The card ships with a GPU clock speed of 925 MHz, PowerTune boost clock of 975 MHz, and 6.00 GHz memory for a memory bandwidth of 192 GB/s.