whats the difference between PCI and AGP?

[Battousai^]

whats the difference between PCI and AGP?

whats better S3 Savage 4 PCI 16 MB or S3 Savage AGP 16 MB?

would it be better to choose PCI instead of choosing AGP if my mobo's AGP slot is 2X? whats the difference between 2X AGP and 4X AGP? what will happen if I inserted 4X AGP card on a 2X AGP slot?

[Alex Iannuzzi]

The main difference between PCI and AGP is that AGP is faster than PCI. PCI is 32 bit and I think AGP is 64 bit.

I would go for the AGP Video Card, it would be faster and in some cases cheaper.

The difference between 2X and 4X is that 4X is two times faster access time that 2X.

:)

[NDC]

Also, PCI is 33Mhz vs. AGP's 66Mhz port...

http://www6.tomshardware.com/mainboard/00q1/000214/

The difference between 2X and 4X is that 4X is two times faster access time that 2X.

Actually it isn't. You won't be able to tell the difference between AGP 2X & 4X with the naked eye. Even in benchmarks, you'll see a small difference...

[Alex Iannuzzi]

Sorry that's just what I thought.

:eek:

[Martingi]

Yes it was really hard to tell the difference..

[Jimstep]

PCI slots must share one bus, so only one PCI device can be communicating with the processor.

The AGP port does not share access to the processor with any other device, so this is a performance boost all by itself. It can do many operations simultaneously with other PCI and processor activities.

PCI bus is limited to 132Mb/sec.

AGP 4x can deliver over 1GB/sec. And with the new AGP 3.0 specification from Intel, 8x can deliver 2.1GB/sec.

Of course, the bandwidth is dependent on the bus speed and the capabilities of the graphics card.

Intel developed the AGP specification, so their website is bound to have a good white paper.

[Kurylo]

To NDC:
No, you're wrong: AGP2x itself is twice faster than AGP1x, and AGP4x is twice faster than AGP2x. This uses the same technology as DDR.
If you can't see this increase of a speed by the test, it doesn't mean that AGP2x hasn't twice bandwidth as AGP1x, foe example.
AGP4X only increases overall system performance by about 3-5%, depending on the test, but it does not mean that AGP4x is not faster. (DDR RAM offers 3-5% increase of a productivity, depending on the test, but that doesn't mean that DDR's speed itself is not twice as SDR).
Here are the specs: AGP1x: 266MB/s; AGP2x: 533MB/s; AGP4x: 1066MB/s.
BTW, 100MHz FSB offers 800MB/s and 133MHz bus offers 1066MB/s. I tell this because you can't reach the full speed of AGP4x interface with a 100MHz FSB and RAM.

Here is the link for those who is interested, I've found to prove my words:
http://www.pcaccelerate.com/Graphics/AGP4X-1/agp4x-2.html

[Kurylo]

And, as you can see, AGP8x had a 2133MB/s bandwitdh (jimstep gas mentioned it before, I just say an exact value). But to have ant benefit, you should have a 133MHz DDR FSB which is equal to 266MHz total (ONLY Athlons) and 100/133MHz QDR which is equal to 400/533MHz total (ONLY P4s), and apropriate DDR RAM for Athlons and RDRAM for P4s.

[Strawbs]

So witha 1.4Ghz DDR Athlon, 133Mhz Bus, 4x AGP,64Mb DDR GeForceIII and 512Mb DDR Ram, I guess I'm maxed out then :D

[Kurylo]

Yeah, you're right !!! :D

[Jimstep]

Originally posted by Strawbs
So witha 1.4Ghz DDR Athlon, 133Mhz Bus, 4x AGP,64Mb DDR GeForceIII and 512Mb DDR Ram, I guess I'm maxed out then :D

I think you have the sweet spot for now.

[NDC]

Yes, Kurylo... Theoratically, you're are absolutely correct. However, the performance isn't anything near the bandwidth numbers or 2X vs. 4X in comparision. There are many people who actually think they WILL get double the performance on 4X cards vs, 2X. I just wanted to make that clear... I'm sure you've tried benching at 2X and 4X? Although the bandwidth is doubled, do you see double the difference in performance? I don't think so... Actually, you won't even see a 50% increase in performance. That was the only point I was trying to make seeing that the original poster of this thread seemed to be concerned about using AGP 2.0 on a AGP 1.0 compliant mainboard. That he's not going to miss much.. hehe ;)

[Kurylo]

If you mean the overall performance, then, yes, it will be almost the same, especiall with a new video cards, which have 32 and more MB of onboard RAM.
The 2x AGP itself is really twice faster than 1x AGP. But what functions lay on this AGP? Textures transfers. But in the newer chips with a lot of RAM you'll transfer to a local card's RAM only once, and that's all. AGP is used only to transfer the commands between GPU and CPU-Chipset too, but here we don't need a 1GB/S speeds, even the speeds of AGP 1x is more than enough.
So, here you will not notice a bir performance increase.
If you really want to see AGP's performance changes, then try a card with a 4-8MB of RAM, or some type of i740 chips. They use AGP fully, because they don't have a RAM needed to hold all the textures.
Try to run any test, which will not use (specially) the onboard RAM, and will hold all the textures in the PC's RAM. You'll notice a great performance increase.
I don't argue with you, NDC. Your last post got me clear about your point of view. I just wanted to make things even clearer.

[NDC]

We have no need to argue, Kurylo! We're all here for two reason... One, to learn, and two, to help... ;)

[Kurylo]

I do not argue. I'm LOL. :D :D :D :D :D :D :D :D.
Hail to you all !!!