nVidia GeForce GTX 470 Fermi - Fermi Architecture Cont.


The result of the introduction of all this geometry manipulation is that the traditional geometry interpretation section of a GPU has needed reimplementing (or at least nVidia thinks it does; ATI kept things more simple with its HD 5xx0 series), moving from a single monolithic geometry setup stage to multiple. This brings us back to the Polymorph engine as this is the part that manages the geometry calculations for each SM.

Similarly, Fermi does away with a single rasterisation engine (the part that manages the conversion of all those 3D triangles into 2D pixels) and instead has four, each of which is partnered with four SMs to form a Graphics Processing Cluster (GPC).

Finally, beyond this we get back to a more familiar layout again with the main thread scheduler presiding over the whole affair along with the Host Interface and memory controllers.

As well as these overarching changes, nVidia has also made a host of more subtle improvements. First up, the CUDA Core has improved handling of both single and double precision floating point calculations and meets the new IEEE 754-2008 standard in this regard. Texture units have also been overhauled including a speed bump and support for new texture compression formats. A new large L2 cache reduces the need to address system memory thus reducing latency as well.

(centre)”’Finally we get AA on foliage in Crysis”’(/centre)

The ROP units now support a new 32x Coverage Sampling Anti-alising mode that provides even smoother and more realistic edge blending. There’s also a new super-sampling AA mode that for the first time allows foliage edge smoothing in Crysis. Overall ROP performance has also been improved through a number of compression and efficiency enhancements. Meanwhile, the addition of larger and better implemented caches improves bandwidth to the framebuffer, greatly enhancing ray tracing speed amongst other things.

A rather more esoteric addition is that of 3D Vision Surround. Like ATI, this is an attempt to find a reason for gamers to invest in multiple high-end graphics cards as conventional gaming arguably doesn’t require such expensive hardware. Essentially, it enables you to play games across three monitors each with a resolution of up to 1,920 x 1,080 pixels, just like ATI’s Eyefinity. However, nVidia has gone a step further adding in stereoscopic 3D support as well. So, if you’re willing to buy two GTX 480’s, three monitors capable of fast enough refresh-rates for 3D, and a pair of 3D glasses then the option is there for truly 3D gaming (in fairness, you can also game in 3D on a single monitor). We, however, didn’t have such a setup with which to test.

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