Rumors have been circulating that AMD would be launching the Radeon HD 7990 soon after NVIDIA launched their Kepler debut card, the GTX 680.
It has yet to happen, but let’s take a look at the rumored specs for the AMD HD 7990 “New Zealand”:
- Two “Tahiti” GPU chips clocked at a lower than HD 7970 speed of 850 MHz, connected via an onboard CrossFire bridge chip.
- 6 GBs of GDDR5 memory clocked at 1250 MHz (5 GHz effective), divided in two for 3 GB per GPU, on 2 x 384-bit buses.
- 62 compute units with a total of 4096 (2 x 2048) Stream Processors and 256 (2 x 128) texture units.
- TDP of ~330 watts (max power use in watts).
- DirectX 11.1 and OpenGL 4.2 hardware support.
- PCI-Express 3.0 compliant.
NVIDIA plans to tackle the HD 7990 with the GeForce GTX 690, a similar dual GPU solution.
The rumored specs for the NVIDIA GeForce GTX 690 at the moment are as follows:
- Two GTX 680 “GK104” GPUs, clocked at lower than GTX 680 speed of ~705 MHz to ~730 MHz (boost), connected via an onboard SLI bridge chip.
- 4 GBs of GDDR5 memory clocked at 1500 MHz (6 GHz effective), divided in two for 2 GB per GPU, on 2 x 256-bit buses.
- 64 Raster Operations Pipelines, 8 Graphics Processing Clusters and 16 Streaming Multiprocessors with a total of 3072 (2 x 1536) CUDA cores and 256 texture units.
- TDP of ~300 watts (max power use in watts).
- DirectX 11.1 and OpenGL 4.2 hardware support.
- PCI-Express 3.0 compliant.
Conclusion:
It’s not that easy to make any conclusions based on the on the rumored specifications of the two dual-GPU cards, but seen in light of the recent test results of their single-GPU equivalents, it seems obvious that it will be a very close race in terms of total performance output.
The AMD card has it’s advantages in memory bandwidth, whereas the NVIDIA card counters the lack of sheer memory size and bandwidth with more speed. You can speculate that this would possibly make a difference in games that have not been released yet, in AMD’s favor, but we can only speculate at this point.
All in all, for current generation games, these cards will be overkill, but may be worth considering if you want to “future proof” your gaming RIG, especially considering the prices these cards are expected to carry, at about 1.5-1.75 times the price of a single GPU version. Even though the GPU clock is very likely to be lower on these cards than their single GPU equivalents, it still means savings over buying a second GTX 680 or HD 7970.
If you’re considering buying one of these cards, it’s worth checking first that it will fit in your rig. The length of these dual GPU cards, especially the AMD cards tend to be very long at over 11.5 inches / 29.2 cm, with NVIDIA trailing right behind at 11 inches / 27.94 cm (lenghts of the HD 6990 and GTX 590 cards).
Release dates are not official, but the GTX 690 is rumored to be released in May, and we could see the HD 7990 released before the end of April.
