The Visiontek GeForce 4
Xtasy Ti4400 128Mb DDR

Friday, May 03, 2002


Introduction

With each new generation of Nvidia graphics cards, new technology has been unleashed on the market. With the advent of the GeForce 3, that technology was the NV20 GPU. Now, it's the GeForce 4 that has taken center-stage, and with it, the NV25 GPU on the Titanium series of this graphic card.

The first thing one might notice about the NV25 is that it's no lightweight. Despite being manufactured using the same 0.15 micron process as its predecessor, the NV20, the NV25 is 5% bigger -- due in no small part to the added transistor count, 62 million in the NV25, versus 57 million in the NV20.


The GPU of the Visiontek GeForce 4 Xtasy Ti4400, for its part, runs at 275MHz, coupled with a 350MHz RAMDAC, and 128MB of 550MHz, 3.6ns Samsung memory.

Contrary to the GeForce 3, the Titanium series of the GeForce 4 product-line uses two Vertex Shaders for fast the Pixel Shaders and 3D textures.

The GF4 Titanium series also uses Nvidia's new "Lighting Memory Architecture II", which is essentially composed of four separate memory controllers, each capable of accessing 32MB of memory. The Ti4400 also includes a new feature dubbed "Auto Precharge", which serves to predict which rows and columns of memory will be used in the near future, and ready them for access. This paves the way for a noticeable performance boost if the technology is used properly, and, better yet, even if it isn't, there should be no performance loss, since the calculations involved are performed separate from the rest of the graphics system. Another new addition is the "Visibility Subsystem", which is designed to determine whether a pixel in a 3D environment is ultimately viewable or if it is hidden by another pixel. If not, the superfluous information is culled from the pack in order to save on memory bandwidth. This method is actually quite similar to the tech behind the Kyro II graphics card, and, together with the rest of the "Lightning Memory Architecture II", promises an up to 300% increase in memory bandwidth efficiency.

The GF4's repertoire isn't limited to new memory tricks however. Nvidia's new antialiasing technology, "Accuview", has also made its debut with the "Titanium" series. "Accuview" offers a new 4X mode under Direct 3D. The mode has been dubbed "4XS", and can antialias 50% more pixels than previous implementations. "Accuview" also permits the use of Anisotropic filtration, for even better image quality. The only question, of course - and one we'll soon be answering, is how well, and how fast the new antialiasing features can be implemented in the real world -- particularly in the realm of 3D games, where even a small degradation in performance can often be quite noticeable.

Now, enough talking. Lets go to the serious stuff and start our analysis of this graphic card.

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