ВИДЕОКАРТЫ

Томас Пабст,  14 августа 1998 Страница:   1 2 3 4 5 6 7

Introduction

This is the response of Real3D, co-developer of the Intel i740 3D graphics chip to Bert McComas' article 'Does AGP Really Improve Performance?', plubished on Tom's Hardware Guide a few weeks ago. I very much welcome this response, because it can only educate the reader even more when he can see topics in different lights. This is what the Tech Section is supposed to be about. I decided to include my very own comments as well, just to make this thread even more controversial and thus more interesting.

Thanks to Chris Stellwag, dedicated Marketing and Communications Manager of Real3D!

This article does not necessarily reflect the opinion of the authors Bert McComas and Thomas Pabst !

Real 3D has prepared the following response to Bert's article 'Does AGP Really Improve Performance?'.  Obviously, as co-developer of the Intel740 and manufacturer of the Intel740-based StarFighter family of graphics boards, Real 3D has a vested interest in their success.  However, we also believe that healthy debate, differing points of view, and open dialogue helps educate potential users about 3D technology and the complexities of 3D graphics.  This response is not meant to be combative; it is meant to present some facts that may have been neglected or misleading in the original article.  Real 3D has had several discussions with Bert regarding the article and our response, and while we may disagree in some areas, we do agree that presenting all sides of a story is fair and desirable.

We're going to first address the questions Bert posed in the article, and follow with a more detailed discussion and analysis.

Is AGP faster than PCI?

Bert McComas: "Yes, but not by much."

Real 3D: AGP is definitely faster than PCI.  The theoretical bandwidths of AGP and PCI are 533 MB/sec and 133 MB/sec, respectively.  With existing systems, we can demonstrate greater than 330 MB/sec through AGP.  Due to contention with other devices on the PCI bus and the lack of pipelining, PCI offers roughly 80 MB/sec.  Even without using any of the extra features of AGP, the AGP bus runs at 66 MHz and the PCI bus runs at 33 MHz so AGP provides double the data rate.

Tom: Theoretical peak bandwidth numbers can easily be used for impressing people. However I may be allowed to ask how much is left of these '4 times faster' when it comes down to real world applications. Isn't it strange that the currently fastest 3D accelerator is called '3Dfx Voodoo2' and comes as a PCI solution?

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Introduction Is AGP faster than PCI? Is AGP (texturing) faster than (texturing from) local graphics memory? Will an AGP2X board be faster than a 1X board?   Isn't it true that any AGP board will be faster than any PCI board? Does graphics accelerator performance improve when AGP texturing is turned on? Does AGP enhance CPU performance? Then why is it that sometimes AGP cards score better than non-AGP on benchmarks? What can I do to avoid the negative performance impact of AGP? What is AGP good for? When that time comes, should I buy a faster CPU or more graphics memory? Technical Background Conclusion  Обсуждение в Клубе Экспертов THG