(Updated to add additional information on the 8900 series rumors – mainly on Radeon 8950.)

Earlier this week, we reported on rumors of two upcoming mid-range AMD 8800 series graphics cards based on the Sea Islands architecture. As mentioned previously, Sea Islands is the successor to the Southern Islands architecture used on the 7000 series. It features an improved Graphics Core Next GPU processor architecture based on TSMC's 28nm process. With that said, the chip will draw less power and be faster on GPGPU workloads thanks to several efficiency tweaks. Graphics cards based on Sea Islands will support DirectX 11, and will be available early next year.

While the 8850 and 8870 are based on the Oland GPU, this newly leaked Radeon HD 8970 will use the "Sea Islands" Tenerife GPU. New information seems to suggest that AMD will actually brand it the Venus XTX for 8970 cards and Venus XT/Pro for 8950 cards, though Oland would remain the chip name for 8800 series cards.

Tenerife offers up some impressive (but realistic) specifications, including 2,560 shaders, 160 texture units, 48 ROPs, and a relatively massive 384-bit memory bus. Also impressive is an alleged transistor count of 5.1 billion, which puts it a great deal above the Radeon 7970's 4.31 billion transistors. This rumored Tenerife/Venus XTX GPU (whichever AMD ends up calling it) will have a 250W TDP and will be use in the 8970 flagship graphics card. Venus XT/Pro will scale back the chip a bit by featuring 2,304 shaders, 144 texture units, and 32 ROPs. No word yet on what the TDP will be.

Both the HD 8970 and HD 8950 are said to support 3GB of GDDR5 memory running at 6GHz on a 384-bit bus, which works out such that the cards have approximately 322 GB/s of bandwidth! Further, the 16 additional ROP units in the Radeon HD 8970 will give it a nice performance boost over the 8950 and 8800 series, especially when running multiple monitors in Eyefinity configurations.

As far as specifications go, we do not yet know the die size of the GPU or what the GPU base (and boost) clockspeeds are beyond a source indicating the boost frequency of the 8970 will be above 1050 MHz. According to PC Perspective's GPU packrat reviewer Josh Walrath, the Tenerife GPU will have a much larger die than that of Oland. Because it will feature a sizeable increase in number of transistors, but still be based on a 28nm process, the die size will be somewhere between 380mm^2 and 420mm^2.

To put that in perspective, the 8850/8870 has a die size of 270mm^2, and the current generation predecessor (7950/7970) has a die size of only 365mm^2.

The following chart compares the various rumored Radeon 8000-series graphics cards to their previous generation counterparts.

  Radeon HD 7850 Radeon HD 8850 Radeon HD 7870 Radeon HD 8870 Radeon 7950 Radeon 8950 Radeon HD 7970 Radeon HD 8970
Die Size 212mm^2 270mm^2 212mm^2 270mm^2 365mm^2 ~400mm^2 365mm^2 ~ 400mm^2 
Shader Count 1024 1536 1280 1792 1792 2304 2048 2560
TMUs 64 96 80 112 112 144 128 160
ROPs 32 32 32 32 32 32 32 48
Memory Interface 256-bit 256-bit 256-bit 256-bit 384-bit 384-bit 384-bit 384-bit
Bandwidth 153.6 GB/s 192 GB/s 153.6 GB/s 192 GB/s 240 GB/s 322 GB/s 288 GB/s 322 GB/s

*Tenerife die size is estimate only, actual die size is still unknown.

The AMD Radeon HD 8970 will be AMD's next generation single-GPU flagship graphics card, and it looks to offer up some respectable hardware. The Radeon HD 8950 should be a decent step up in performance versus the 7950, though it would have been nice to see the 8970's additional ROP units stick around in the 8950. Unfortunately we do not know what this Tenerife (aka Venus) GPU-based  graphics card will be priced at. For now, we will just have to be cautiously optimistic and wait a few months to see how much this card will cost. The wait should not be very long either, if rumors are true as they seem to indicate that the 8970 will enter manufacturing in late 2012 and launched in early (January/February) 2013.

Are you excited for AMD's next-generation flagship?