AGP vs. PCI Express.

[Somethindarker]

Last night I was looking through my comps stats and i saw that my comp is AGP other than my friends PCI express. He told me that PCI is slightly better than AGP because AGP is an older technonlogy and PCI had more "potential" or more ability to "expand". ME? Well my comp is gonna be upgraded either way so I just want to know whats the difference and will it really matter in the long run. This is gonna be the last time I upgrade it and I'd just want to know for when I buy another better one after this one has become obselete.

[Gaius Baltar]

All systems are going to have the PCI graphics, which produces higher aand faster rates of throughput.

In a word, AGP is obsolete,

[Incinerate_IV]

All systems are going to have the PCI graphics, which produces higher aand faster rates of throughput.

In a word, AGP is obsolete,

Just to clear things up PCI is NOT the same as PCI-Express, they are not related in any way.

And like what everyone else says, PCI-Express is the future. You can still get a AGP graphics card, but when compared to the much cheaper PCI-Express graphics card you will be riped off.

[Richard the Lionheart]

PCI Express is somewhere around 16x faster than AGP.

[Meqon-Nerd]

aaa damb...ive got AGP...im gona have to upgrade soon, And does it realy go 16x faster???
WOW

[Shadow_Imperator]

AGP maxes out at x8 I think, where as PCI was released at x16 and from what I heard, can and will be pushed up to x64...

[Aristocrat]

At the moment there is no difference in how well games run on either AGP or PCI express.
That will change, as PCI-express can transfer data quicker, but no game at this time takes advantage of it, so upgrading one last time isn't that bad an idea...except that the price of AGP cards is climbing as companies stop making them.

[Evariste]

Comparing PCI Express to AGP is like comparing USB 2.0 to 1.1. Eventually the latter will be obsolete.

[Hadrian]

[/QUOTE] Well my comp is gonna be upgraded either way so I just want to know whats the difference and will it really matter in the long run. This is gonna be the last time I upgrade it and I'd just want to know for when I buy another better one after this one has become obselete. [QUOTE]

Well,you've already made up your mind about upgrading you AGP card but just know this,the advice of the others is accurate.PCI-E is here and has already established itself as the future.AGP is becoming rapidly obsolete and it will definately be the last time you have an opportunity to upgrade that type of GPU.Its a dead end road.The only reason you can still purchase an AGP video card is the commitment of the GPU manufacturers to tap the last bit of revenue out of a dying market while appearing to be loyal to stranded customers!I think Incinerate_IV says the best one left is the 7800GT or GS,I'm not sure....

[PyrrhusIV]

PCI Express is somewhere around 16x faster than AGP.

No, that's not right at all. AGP 1x is 2X faster than PCI, 2x is actually 4x, so by the time you get to 8x , AGP is 16x faster than PCI. The PCI bus can only allow 144MB of data per second...so

144 x 16 = 2,304 MB's per second (AGP 8x)

The same applies to PCI-Express mostly:

AGP 8x = 2,304 MB's per second + 1152 (Transfer of PCI-Express 16x) = 3,456

Remember, those data rates are the max, and only theoretically can be reached. Right now though, you really cant tell the difference between the Best AGP card & the Best PCI-Express. Well, you probably could tell a small difference, but that is only because of the huge emphasis to throw all the new technology into PCI-Express. Of course, your computer is as fast as it's slowest component, usually your HDD or RAM.

[sunsmountain]

http://en.wikipedia.org/wiki/Accelerated_Graphics_Port

AGP 8x, using a 32-bit channel operating at 66 MHz, strobing eight times per clock, delivering an effective 533 MHz resulting in a maximum data rate of 2133 MB/s (2 GB/s); 0.8 V signaling.

that's 2 GB/s one-way, from your cpu/chipset TO the graphics card, not FROM. Usually you don't need a lot of data coming from your graphics card to anywhere else unless you're doing stuff like video editing. Under Windows Longhorn however, Vista and Direct X 10 / WGF 2.0 will start making use of small graphics "pages" (containing a shader, vertex or texture element) which can be transferred and processed anywhere, but mainly the CPU (what, with all the extra cores and such, you gotta use them for something, right?).

Meanwhile:

First-generation PCIe is often quoted to support a data rate of 250 MB/s (238 MiB/s) in each direction, per lane. This figure is a calculation from the physical signalling rate (2500 Mbaud) divided by the encoding overhead (10bits/byte.) This means a 16 lane (x16) PCIe card would then be theoretically capable of 250 * 16 = 4000 MB/s (3.7 GiB/s) in each direction.

So that's 4 GB/s two-way. PCI xpress lanes are 250 MB/s while AGP/PCI lanes are 266 MB/s, but PCI xpress lanes are better dedicated and do not use the universal 32-bit mobo bus over which all other traffic travels.

[Hadrian]

And Antoninus is right to say that most of the head knowledge is being channeled into the dominant PCI-E market, so it tends to be the focus of all the new technology whereas AGP gets what technology can be transferred over and altered to fit the AGP platform.
Did all those numbers add up to say that, the two graphics platforms are similar in bandwidth/speed but the PCI-E can transfer data in both directions,so technically,(no pun intended)PCI-E is....better?

P.S. sunsmountain,your going to educate yourself to a level of technical expertise, where none of us can understand what your talking about!

[krazykarl]

One of the big advantages PCI-e has over AGP is that AGP is a point to point bus, meaning that you have 1 agp controller in your northbridge, you can have 1 AGP slot. This differs from conventional PCI and the newer PCI-e, as both these busses operate in paralell. Regular PCI could have upto 6 slots (mind you I think only 4 could be bus-master PCI) where as PCI-e can have as many slots as you have 'lanes'. PCI express is actually a combination of several smaller serial piont to point busses (the lanes) PCI x1 uses 1 lane, and has as much theoretical bandwith as PCI (133mb/s) and will be used for future low bandwidth peripherals (soundcards etc) Graphics cards use PCI-e X16, which as you may guess has 16 lanes. BUT not always, here is the kicker, One of the features of a specific chipset is the number of 'lanes' it supports. For example the Nforce 4 supports 20 fixed lanes, meaning you have 16 for the graphics and 4 for the x1 lanes. The Nforce 4 SLI also sports 20 lanes, but it is in 'flexable' mode, allowing the manufactuer to control the lane allocation via the BIOS, so to enable an SLI system you can run 2 phisical X16 slots on 8 lanes each, cutting your theoretical bandwith in half, but saving some money. The Nforce 4 SLI x16 chipset supports 40 flexable lanes, and each Graphics card in an SLI setup gets 16 lanes

Nvidia chipsets
http://www.nvidia.com/page/nforce4_family.html

Hope this helps.

-Karl