Conclusion

In all, the AGP GeForce 6600 GT throws up few surprises in relation to the PCI Express version in terms of gaming performance, once we factor in the decrease in memory bandwidth. The overall gaming performances come in at around 8% below the PCI Express version in graphics limited cases, but given the generally high performance of the 6600 GT’s this isn’t too much of an issue. The only times this difference increases is under high resolution FSAA situations, where some textures are pushed over to system RAM and so the performance of the graphics interface becomes more critical – given that this only occurs at high resolution with high FSAA levels its questionable whether the performances would be viable in these situations anyway.

The decision to clock down the memory on the AGP version, in relation to the PCI Express 6600 GT board, is a little curious, although there may be a few potential explanations. What we may think as being an obvious one, cost, isn’t quite as obvious as it seems – the inclusion of an extra chip, the HSI bridge, will increase board costs so something may be cut back to offset that cost, however in the case of the memory the same 2ns modules are being used on both AGP and PCIeversions, so the physical memory costs will be the same for both models. Potentially there may be validation costs savings at the board level, or possibly the layout of the board makes high speed routing a little trickier. Another potential reason may be that this is being used as an incentive for people to upgrade from AGP to PCI Express systems by only offering the highest performance on the PCI Express boards – it wouldn’t surprise us to see this occurring more frequently as the push to PCI Express becomes more prominent.

The inclusion of the GeForce FX 5800 Ultra in this article also highlights exactly the importance of a flexible shader pipeline in current gaming titles. The top level fill-rates and geometry performances between the 5800 Ultra and the newer 6600 GT’s are fairly similar, and yet in gaming titles, even DirectX8 ones that rely heavily on multi-texturing and not so much on shaders, the 6600 GT’s show large performance gains over NVIDIA’s two year old high end technology. The performance delta’s are widened with more recent DirectX9 titles that make frequent use of shaders within the applications, and the under the Counter Strike Source Video Stress Test the 6600 GT, running DirectX9 shaders is even able to outperform the 5800 Ultra running DirectX8!

The GeForce 6600 GT now gives AGP system owners a good high performance, but cost sensitive choice.