I just upgraded my PC over the weekend and among the upgrades was a new motherboard. The new motherboard has all the bells and whistles one could ask for including support for 4x AGP (Advanced Graphics Port) video.
I seem to recall however that 4x AGP was always kind of a joke and never amounted to much in practice. In fact, if memory serves, enabling 4x AGP actually slowed your graphics processing down. 4x AGP allows the video card to use system RAM to store data in. Unfortunately todays video cards are running at such a high speed that the time to cross the system bus and back seriously degrades performance. 2x AGP forces the card to use only its onboard RAM (which is not only phisically closer but generally tends to be faster than most system RAM specifications…in my case 32MB of DDR RAM on a GeForce video card).
So, is 4x AGP really not worth enabling? I can’t find the articles I once read that discussed this issue. My brain keeps saying, “4x HAS to be better than 2x doesn’t it?” I know that this necessarily isn’t true but confirmation on my vague recollections would be nice.
Computing: 50 Hot Technologies
January 2000• Vol.8 Issue 1
AGP 4X
Faster Data Transfer & Better-Quality Images
Small part of Article below
AGP 4X Versus Earlier Versions.
AGP 4X is the current version of AGP. The original version of AGP was referred to as specification 1.0. AGP 1.0 defined two different card speeds: 1X and 2X. The AGP 2.0 specification adds support for the 4X speed.
All AGP cards have a clock speed of 66 megahertz (MHz); the difference between AGP speeds is not the card’s clock speed, but how many transfers the card makes during a cycle. AGP 1X makes a single transfer per cycle for a maximum data-transfer rate of 266 megabytes per second (MBps); about twice as fast as the 33MHz PCI slot. AGP 2X makes two transfers per cycle, making its maximum data-transfer rate 533MBps. The latest AGP 4X boasts a maximum data-transfer rate of 1,066MBps. Obviously when you’re dealing with 3-D animations or any other full-motion video environment, faster data transfer is better.
Your System Requirements.
To fully take advantage of AGP 4X, you need the following:
·an AGP 4X video card and an AGP 4X-compatible motherboard, or a system with integrated AGP 4X video on the motherboard
·a CPU and memory modules that support 133MHz system bus speeds
Here’s an older article from 3 years ago that parallels your concerns.
AGP: What’s in It For You?
In theory, AGP represents a revolutionary advance for 3-D graphics boards. But in practice, its performance gains may affect only a small group of users
I think the state of the art has advanced to the degree that modern motherboards and memory sub-systems can take advantage of 4X vs 2X transfers if you are gaming and have a high performance card and system.
In all the reviews I’ve seen of video cards, new and old (say, TNT2s to GeForce2 Ultras), there was always an aside, just a sentence or two, saying that 4x has not yet shown any significant gain over 2x. There might be, at best, a 2 frame advantage in the Quake 3 benchmarks, but that’s it, AFAIK. I’ve never heard of it actually causing a performance hit, however.
Seems to me that it would most likely have the most benefits in texture heavy games. In 2d apps, or older 3d games you won’t see any speed increases. Even in the largest quake 3 maps, about 90 mb of textures are used in the entire level. I doubt that the entire 90 mb of textures will be used in any given scene (or even within a room) so transfer rate on a 32 mb - 64 mb card won’t be that critical.
I’d leave it on just in case, though. If your card supports fast writes it can only help.