Southern Islands and Tech
Specs and Southern Islands
Southern Islands
As weird as it might sound, we are going to talk about a couple of islands first. You've been hearing about several codenames and that can be a little confusing. AMD codenamed their 6000 and 7000 product series after islands in the Northern (6000) and Southern (7000) hemisphere.
It's simple really, in the market we have entry level, mainstream and high-end products. When you notice "Verde" that's entry level. "Pitcairn" will be the codename the mainstream products will hide under, and finally "Tahiti" is the codename for the most high-end products.
- Entry level = Verde = Radeon HD 7700 series
- Mainstream level = Pitcairn = Radeon HD 7800 series
- High-end level = Tahiti = Radeon HD 7900 series
The entire segment from top to bottom was released in 2012, along with the second product series, the Radeon HD 7950.
Technology
Albeit we test the Radeon HD 7870, we'll focus on the 7900 series today of course as this specific product used that 7900 Tahiti chip. It is important to understand that there are significant changes in this family of GPUs. The GPU architecture was overhauled, AMD moved over to a 28nm process technology, the new cards are PCIe gen 3 compatible and there have been significant changes on power consumption. We'll address all the features separately of course. With the launch of the Radeon HD 7000 series Eyefinity was updated to version 2.0. DDM audio is now fully supported (you hear audio on the actual monitor it's played off), a new 5x1 landscape mode is introduced, and you may now create custom multi-monitor resolutions. But let's break things down.
Meet Tahiti
AMD bakes GPU's on the all 28nm node, in very simple wording that means they can put more transistors on a smaller area. The Tahiti core has a nice 4.3 Billion transistors, 4,312,711,873 to be precise. The internal architecture has changed, we'll talk a little deeper about that in a minute.
Tahiti Pro (R7950)
The R7950 is packed with 1536 shader processors harbored in Compute Units segments (24 of them). Memory volume wise the card will pack 2 Gigabytes of DDR5 memory. The memory bus has been kept at 256-bit.
Tahiti LE (R7870 Joker card)
The 7870 Joker card is packed with 1536 shader processors harbored in Compute Units segments (28 of them). Memory volume wise the card will pack a whopping 3 Gigabytes of DDR5 memory. This is not done for bragging rights, but AMD simply takes Eyefinity and multiple monitor usage very seriously; it is there where the extra memory makes a lot of sense. The memory bus has been increased from 256-bit to 384-bit as well.
Packing so many transistors on a product is staggering, but if you can't apply a fast enough clock frequency it would become a problem. Well, that's not an issue for AMD either, the R7870 Joker is clocked at 925 MHz at reference with the Boost allowing 975 MHz. That 256-bit memory is a bit cut down, but still impressive speeds as well; 6 Gbps, that's bandwidth up-to 192 GB/sec.
