Expreview found two photos and the first preliminary benchmarks of the upcoming dual-GPU GeForce GTX 295 graphics card from NVIDIA. The site says the GeForce GTX 295 will feature two 55nm GPUs clocked at 576MHz, with 1242MHz shaders and 1792MB GDDR3 memory clocked at 1998MHz. Each GPU features 240 shaders, and has a 448-bit memory bus. The TDP of the card is said to be 289W, only 3W more than the TDP of the ATI Radeon HD 4870 X2.
As we said, GTX295 won’t use GDDR5. Its core/memory/shader frequency is 576/999/1242, the same as GTX260. But the total video memory/memory interface (1792MB/896bit) have doubled that of GTX260. The stream processors (480) of GTX295 also doubles that of GTX280.
Here's a slide that compares the performance of the GeForce GTX 295 with the Radeon HD 4870 X2. Take it with a grain of salt, but it appears the GeForce GTX 295 may have a significant performance advantage over the Radeon HD 4870 X2.
There's also a PhysX benchmark on Expreview's website and a power consumption comparison. If these figures are correct, the GeForce GTX 295 will have a much better performance per watt than the Radeon HD 4870 X2.