When AMD and NVIDIA release a new batch of next-generation graphics processors, gaps typically form in their respective product stacks as the entire top-to-bottom line-up of new products is fleshed out over time. When new GPUs are introduced, they usually offer increased performance at a given price point, which drives the cost of comparable previous-generation products downward. Occasionally the supply and demand of both the new and old products will result in a larger than desired price disparity between the new parts and the older ones that still remain on the market. It’s those large price disparities that are where product gaps show.
Such is the case with AMD’s current product stack. At the top of the line-up, AMD has the Radeon HD 6900 and 6800 series parts, but the lower-end of the market is still covered by Radeon HD 5000 series parts. Disregarding the few remaining Radeon HD 5800 series parts that will eventually sell out, the $100 to $120-ish Radeon HD 5770 is currently the first step down from the $150 to $180-ish Radeon HD 6850. AMD aims to fill that relatively large price gap between those two models with the new card we’ll be showing you here today, the Radeon HD 6790.
This first official member of the Radeon HD 6700 series isn’t completely new (we say official because the Radeon HD 6770, which is a re-branded 5770 is available to OEMs). In fact, it is based on the very same "Barts" GPU powering the Radeon HD 6800 series. A few functional blocks within the GPU have been disabled, however, ultimately resulting in a lower performing, but decidedly more affordable, DirectX-11 class GPU. We’ve got the full specifications, details and pics below. We'll then take a look at performance on the pages ahead.
Memory Bus Width
Memory Data Rate
Load Board Power
Idle Board Power
Up to 840 MHz
Up to 1.34 TFLOPs
Up to 1050 MHz
Up to 4.2 Gbps
Up to 134.4 GB/s
We’re not going to harp on the physical attributes of the Radeon HD 6790 we tested for a couple of reasons. First off, according to AMD, the card you see pictured here will never see the light of day. It is a reference model based on the same design as the Radeon HD 6850. Secondly, all of AMD’s board partners are readying custom Radeon HD 6790s that will look nothing like the reference card and may even sport only a single power connector.
The reference Radeon HD 6790 you see pictured here is built around the 40nm ‘Barts’ GPU, which is comprised of roughly 1.7B transistors. As it is configured on the Radeon HD 6790, the GPU will sport 800 stream processors, with 40 texture units, and 16 ROPs (Radeon HD 6850 cards have 960 stream processors, 48 texture units, and 32 ROPs). The 6790 does, however, have the same 256-bit interface to its GDDR5 RAM. This reference card has an 840MHz GPU paired to 1GB of 1050MHz memory (4.2 Gbps data rate), for a peak textured fillrate of 33.6GTexels/ s and 134.4GB/s of memory bandwidth. Idle board power is rated at 19W with a load power of 150W.
Outputs on the Radeon HD 6790 consist of dual DVIs (one dual-link, one single-link), dual mini-DP outs, and an HDMI port. Board partners may choose to different output configurations with their custom designs, however.
Before we move on to the Radeon HD 6790 performance evaluation, we want to point out that custom, factory overclocked Radeon HD 6850 cards, like the HIS Radeon HD 6850 iceQ Turbo, have recently hit the scene at price points not much higher than the 6790. Competing parts from NVIDIA, namely the GeForce GTX 550 Ti, were also available in factory overclocked editions from the get so. As such, we’ve included numbers from some of these factory overclocked cards, alongside the reference clocked models, to paint a more complete picture of performance at all price points ranging from about $149 to $179.