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AGP4X vs. AGP8X
An anonymous reader writes "With upcoming chipsets such as the SiS648 claiming support for the latest AGP8X standard, we asked ourselves if there were any performance benefits. We took the SiS648 and Xabre 400 reference boards, modified them and compared the results." I can't even get 4x stable under XP, so I figure 8x is
half as likely to let me play NWN :)
This review / test is bullshit. The only reason that they see an improvement in lower resolutions is that its the only resolution where the game / app is not limited by the video card.
/. editors will stop "jumping the gun" and wait until some real reviews come out. This is like testing a new high performance tires that can go upto 400/mph with a Yugo. Is anyone going to be surprised when the $25 tire performs just as good as a $400 tire? Sorry for the lame analogy, haven't had my morning Coke. :-p
I'd definitely take this with a grain of salt until someone can do a 4x/8x review with a NV30 or a ATI 9700.
What kind of hardware guy looks at this and doesnt say "WTF Xabre 4000?? What kind of video card is that to benchmark anything?"
Hopefully the
-- D3X
Well, when AGP 1x was out, people didn't find it very useful because it wasn't fast enough
AGP2x was okay to offload the PCI bus and do some basic stuff, but not fast enough for high-speed games and transfering large chunks of information.
Not fast enough to be useful? What reviews were you reading?
Back when AGP 1x and 2x were rolled out, they were found to be marginally useful because the graphics card was the bottleneck. This is true even today. Fill rate is still almost invariably the bottleneck for performance, and CPU power for geometry and physics is usually second.
The original intent of AGP was to transfer textures across the bus, with the card's texture memory just a cache of this data. But this is a _bad_ thing to do - bandwidth and especially latency of a card's on-board memory is likely to be much better than AGP transfer bandwidth and latency, so nobody in their right mind writes games that require streaming textures from system memory. This isn't going to change - the memory in your PC is optimized for being big. The memory in your graphics card is optimized for being fast. Even with a zero-latency, infinite-bandwidth AGP port, local memory is better.
All AGP is used for now is to transfer geometry data, and it's plenty fast for that (cards are still generally fill-rate limited). With on-board transformation and lighting, and further folding-in of the graphics pipeline on the way, the amount of data that needs to be transferred per frame is going to get _smaller_, not larger.
Very high AGP transfer rates are a marketing bullet-point, and not much else.
Oh, and if you're editing a 1600x1200 movie on a PC, you're limited by your disk transfer rate. No way are you storing *any* significant chunk of that in a PC's RAM.
This tomshardware article from a while back compares AGP 1x -> 4x... here were the results. You can see that even in the beginning of 2000, the benefits of higher AGP speed showed diminishing marginal returns.
My server