AGP VS PCI

icepick1

Member
Jul 15, 2000
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What makes AGP so different besides the power conection directly to the powersuply. Does it have to do something with the address and data lines or the busses involved?
 

Tates

Elite Member
Super Moderator
Jun 25, 2000
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AGP is designed to run @ 66Mhz, PCI @33 Mhz. Most newer vid cards are design to the AGP spec, which allows 2x or 4x memory access.
 

Kill_Phil

Golden Member
Nov 14, 1999
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AGP is designed specifically for video cards, it increases bandwidth to the memory from the video card so the video card can read and write to the system memory quicker than through the pci bus. this also allows the agp card to use the system memory as part of its own memory if it runs out of space on the onboard memory for textures (useually on 8 meg cards, most 32 meg cards dont require this) then there is agp sidebanding which adds a few extra bits to the agp bus for the video card to send extra controll bits. opposite to what it was intended fo (speeding up the agp card) this actually does not improve performance, yet it does decrease stability

if im wrong with any of this, someone correct me =)
 

RSI

Diamond Member
May 22, 2000
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All the 'specs' for AGP look nice, but then I hear things like it doesn't improve performance and decreases stability... for cards like the Banshee (which I have downstairs in PCI format) AGP is not worth it, because it was based on old Voodoo II technology and it doesn't make use of the features, blah blah blah...

But on newer cards like GeForce-this and GeForce-that's, wouldn't AGP be excellent? But whatever, lol...They gonna come out with somethin' better any time soon? Anybody know?
 

compuser

Member
Feb 14, 2000
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icepick1, to make things simple (and this is assuming that you are debating whether to buy a pci or an agp card...), agp and pci differences have already been pointed out by others. however...

however, from a usage need and purchase point of view, if you are not going to be playing games, just working with business apps or heck, even graphics apps like photoshop, there really is no need to go with agp... if $$ is the issue... since all this involves only 2d and not 3d rendering by the vid. card. vid cards don't require obscene amount of memory for 2d rendering. thus the available vid. card memory (esp on the newer ones) will prove sufficient for the job at hand and the card won't have to use system memory. in this case, there is no point of having an agp (whose main advantage is to increase the bandwidth of the direct channel between the card and system memory.)

bottom line, if you are not going to be playing games, rendering or the like, and if $$ is the issue, go with pci else, agp. one thing i must point out, with the agp becoming the most popular standard for vid card bus format, some pci card prices have started matching those of agp, and sometimes they have even been higher than the agp counterparts. so keep that in mind before u make a purchase for a specific card.
 

Descend492

Senior member
Jul 10, 2000
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ALso, I've run out of PCI slots on my motherboard, and need to buy a lan card (PCI) so I'm forced to buy an AGV vid card to free up an extra PCI slot. Do a tally of how many PCI slots you think you'll need in the future and plan ahead. Luckily it's time for me to buy a new VC anyway
 

Goi

Diamond Member
Oct 10, 1999
6,772
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AGP isn't a bus, its a port, hence the P in AGP. It doesn't share its bandwidth with any other device in the computer, and bypasses the North/South bridges for direct access to the CPU and memory if I remember the system block diagram correctly.
 

Ulysses

Platinum Member
Jun 17, 2000
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I use dual monitors and, at least with Win 98, you can only do this with PCI graphics cards, except for something like the Matrox G400 series.
 

CQuinn

Golden Member
May 31, 2000
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I thought you could do an AGP card alongside a PCI to enable
dual monitor support? What you need to do is enable to
BIOS to recognize the AGP card as primary video device.
 

icepick1

Member
Jul 15, 2000
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Well thaks for all the replies. I know the difference between the two now. I guess it sounds like they should develop a better bus for the AGP to work on. I think someone said 66mhz. If they can get memory bandwidth up to 133mhz why not agp?

thanks all,

Ice
 

Goi

Diamond Member
Oct 10, 1999
6,772
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You CAN run a dual monitor setup using an AGP card along with a PCI video card. Obviously 2 AGP cards won't work since there's only at most 1 AGP slot in a motherboard.

icepick, as I said AGP is a port, not a bus, so what do you mean when you say they should develop a better bus for the AGP to work on?