NVIDIA GeForce GTX 295 is based on two GT200b cores that are produced in a 55 nm process. With the "old" 65 nm GT200 it was not possible to create such a dual card because of the higher power requirements and heat output. The basic thermal design of the card follows the one introduced with the 9800 GX2 which uses a heatsink sandwiched in between two PCBs which each have their own GPU and memory.
In order to achieve the performance target, the GeForce GTX 295 uses SLI to make both GPUs work together. However, as end user you will not notice anything of that. You just install the GTX 295, install the driver and it works - without ever mentioning SLI.
HD 4870 X2
|Shader units||112||800||128||192||800||240||2x 800||240||2x 240|
|ROPs||16||16||16||28||16||32||2x 16||32||2x 28|
|GPU||G92||RV770||G92||GT200||RV770||GT200||2x RV770||GT200b||2x GT200b|
|Transistors||754M||956M||754M||1400M||956M||1400M||2x 956M||1400M||2x 1400M|
|Memory Size||512 MB||512 MB||512 MB||896 MB||512 MB||1024 MB||2x 1024 MB||1024 MB||2x 896 MB|
|Memory Bus Width||256 bit||256 bit||256 bit||448 bit||256 bit||512 bit||2x 256 bit||512 bit||2x 448 bit|
|Core Clock||600 MHz||625 MHz||675 MHz||576 MHz||750 MHz||602 MHz||750 MHz||648 MHz||576 MHz|
|Memory Clock||900 MHz||993 MHz||1100 MHz||999 MHz||900 MHz||1107 MHz||900 MHz||1242 MHz||999 MHz|