How NVIDIA decided to accelerate the GeForce 9600 GT unnoticed by users
In the conclusions of the first GeForce 9600 GT reviews, various resources were unanimous in their opinion – this is one of the most successful mid-range accelerators.
However, a small circumstance that contributed to the achievement of excellent results by the novelty remained behind the scenes. RivaTuner Overclocking and GPU-Z software take data on the frequency of the GPU from the driver, and therefore demonstrate 650 MHz for models not overclocked by the manufacturer. At the same time, the RivaTuner Monitoring module has direct access to the frequency generator, and its readings may differ from those obtained in the above way.
The supposed explanation for this fact is the difference in the method of determining the frequency by the driver, which uses the default value of 25 MHz, and the actual step of the frequency generator, which depends on the frequency at which the PCI Express bus operates.
The source carried out measurements in the test for measuring the fill rate in multitexturing mode in 3DMark06, and the measurements confirmed the assumptions – the result grew in proportion to the increase in the frequency of the external bus. The GeForce 8800 GT was stable regardless of the PCI Express frequency.
A latent threat in this case will exist for owners of GeForce 9600 GT and motherboards supporting LinkBoost technology, which automatically increases the PCI Express frequency when an NVIDIA video card is detected. Not all accelerators will be able to work with such a considerable overclocking of the core frequency (up to 812.5 MHz from the nominal 650 MHz), which means that stability problems are inevitable.
Why NVIDIA chose not to educate buyers and reviewers about its innovation? No official comments yet.
We, in turn, will pay special attention to this issue in our future reviews of GeForce 9600 GT.