AGP vs PCI graphics

Building a new PC requires deciding on an AGP or PCI motherboard. Nvidia's Quadro FX adaptors seem to be great performers but is one (AGP) better than the other (PCI)? All responses appreciated.

Reply to
Mike Pagel
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AGP would be much faster then PCI. Unless you meant ExpressPCI. Then they would be about equal today, but in the future ExpressPCI will have the edge.


Mike Pagel wrote:

Reply to
Paul Gress

PCI Express is the next generation graphics bus and is the natural choice when bying a new PC.

Reply to

PCI Express x 16 is available and already faster than AGPx8

Reply to
Robert Salasidis


"better than the other" for what? You mean to run Pro/e? If so, the answer is no, it doesn't matter. It is technically so irrelevant that it's never even mentioned in the definition of PTC's Certified/Supported systems or graphics cards. If you can save $100 on an nVidia Quadro FX3000 with the AGP bus, get that one. I doubt that it would even make a difference to Pro/e whether it was AGP 4 or 8. The right driver for your card based on the processor, OS and date code of Pro/e is a MUCH bigger issue. I wouldn't buy (or put together) a system without consulting this list:

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Even if you're not buying an HP or Dell workstation, you should still make yours as close to a known, certified/supported hardware configuration as you can. This list also tells what the appropriate drivers are for a particular setup. Now that's not to say that Pro/e won't run on the $1000 gaming machine with a $300 video card. The problem with such hardware is that the motherboards don't support as much memory or as fast processors as you'd like and the GPUs have hardware support for DirectX 9 which does Pro/e no good and little or no support for OpenGL which hurts Pro/e, causing freezes, CTDs and BSODs. nVidia actually sells plenty of those gaming type cards too. What graphics cards and hardware configurations are you considering? While I've thought for a while about putting one together, I get lost just trying to sort out motherboards.

Reply to
David Janes

The point is that AGP is beeing replaced by PCI Express, currently most graphic cards comes in both versions but this might not be the case in two or three years.

Reply to

"David Janes" wrote

and doesn't come with any type of support in case you run into any trouble.

That's not true. First, _all_ Quadro GPUs are basically Geforce GPUs (yes, the cores are identical). The same is valid btw for all ATI FireGL cards (except the ancient FireGL 2/3/4 and the older cards made by Diamond) which are basically Radeon cards. The only difference is the cards BIOS, and a few resistors that decide if the GPU IDs itself as Geforce/Radeon or Quadro/FireGL (and of course other addons like more memory and stereo out on the professional boards). With Nvidia, even the drivers between Geforce and Quadro are identical (the certified Quadro drivers are just plain ForceWare drivers that have been certified). ATIs FireGL driver set shares the Direct3D part with the Catalyst drivers for Radeons but have a different OpenGL driver than the Radeons (the Radeon Mobility also uses the same OpenGL drivers like the FireGL Mobility).

We tried Pro/E and other MCAD applications on several Geforce cards. Except some problems which were caused by the drivers (the problems also were pertinent when running these drivers on a Quadro) the Geforce cards runs these apps as good as a more expensive Quadro card. Of course the Geforce cards lack certain features like AA lines, there is no certification, and of course if one experiences problems there won't be any support. But say for a student who wants to make his first steps a Geforce card is a valid alternative.

As to Radeon cards (desktop, non-mobility versions), well, we experienced several problems with them. The OpenGL driver of the Catalyst driver isn't very good. On notebooks, the experience is much better. Our Radeon Mobility systems had no problems with OpenGL apps.

If you want to build a real workstation from generic parts, I'd say avoid that. Especially since complete workstations (i.e. HP xw8200 and xw9300) usually can be had for the same price - with real service...


Reply to
Benjamin Gawert

Ahh, I forgot about softquadroing. Good you mentioned this. Any of the tecnical stuff (what cards you can do this with, techniques, etc) is MOST welcome. Maybe I can finally get my Geforce2 Go card running right.

Drivers drivers drivers... that's always a big deal. And, yes, nice distinction: softquadroed gaming cards for students. However, that leaves a MUCH narrower range of cards for the professionals

Good point, service is a big deal. That and the decent price of a baseline workstation from Dell or Compaq is certainly the reason I started there. But, by the time I got to the system I really wanted, I was suffering sticker shock ~ $3500-$4500 dollars!!! Now, admittedly, I haven't really dug into this yet, but I'm guessing I could get a comparable system, built from parts, for about $1000 to $1500 less.

BTW, let me say I'm happy to finally meet someone here who knows the intimate details of soft quadroing gaming cards (geforce to quadro fx). I've studied this for a while, trying to improve my Toshiba and got nowhere. It is supposedly possible. This would make a MOST USEFUL ADDITION to the only official FAQ for, a graphics card survey by a Columbia prof named Blair McIntyre. He is still listed as the maintainer but the documents haven't been updated since the mid '90s. Interesting presentation, though. And an issue that's certainly worthy of being kept up to date.

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BTW2, you said nothing on this hot AGP v PCIe "controversy". Seems, in fact, like you avoided it, Benjamin. How come? I'm sticking to my contention that it's a nonissue regarding Pro/e performance. What's your take on it. Technical details would be a welcomed breath of fresh air in contrast to all the stale marketing hype we've heard so far. Someone needs to deal with the fact that, in head to head tests of systems with AGP 8 v PCI-e 16 cards, the reputed doubling of the PCI-e cards bore no fruit: the cards have shown comparable results for the two years that PCI-e has been out. Disappointing for PCI-e; no wonder everyone points to the future.

Reply to
David Janes

"David Janes" wrote

Be careful I think you are mixing something up. In the first place, this all has nothing to do with tools like SoftQuadro (these tools just use the cirumstances I described for their function).

Let me go back in history: Years ago, there was a clear separation between consumer and professional gfx. Consumer cards either were 2D only (with great new features like video playback acceleration) or had very basic 3D capabilities with a very limited function set which was enough for games. These consumer cards already were single chip designs where the complete GPU (exclusive RAM and on older models also the RAMDAC) was made as one IC, and these cards used unified memory (one memory for everything). On the other sides, there were professional gfx boards for PCs and workstations. These cards were discrete designs with lots of ICs where every chip was for a certain function (i.e. Raster processor, texture, geometry etc), often also combined with separate memory subsystems (i.e. separate memory for frame buffer and textures). And these cards were hell of expensive which also due to the high production costs of the dozen or so different processors. As time went by, the mass market consumer cards got better and better, and the product cycles got shorter and shorter. On the other side, professional gfx card development went a lot slower, because of the higher costs and the lower sales figures (and other things like the demise of the traditional RISC workstation market). Very soon, cheap consumer card were able to catch up (or even surpass them!) with professional cards that cost several thousand dollars performance-wise. Nvidia realized very soon that their TNT2 chipset (which already had a fully working OpenGL driver) does extremely well against expensive professional cards like the ones from 3DLabs, and together with Elsa build the first professional gfx card based on a consumer GPU (Gloria Synergy II, GPU came from Nvidia, drivers from Elsa). Due to the success Nvidia increased its effort in the professional market. The (at that time new) Geforce256 consumer GPU with DDR interface was also sold as Quadro for the professional market (Nvidia had the drivers certified). The GPU was identical to the Geforce256 GPU. The difference is only a set of resistors that tell the GPU if it should identify itself as "Geforce" or "Quadro". The unified driver checks this identification and if the GPU says "I'm a Quadro" the driver enables additional features (i.e. AA lines), alters it's performance and quality settings, and offers more settings in the control panel. That's it. The same is valid for all other Quadros that followed, they are identical to the corresponding Geforce GPUs. The only difference is in the layout of a few resistors on the PCB and in newer models also the BIOS. BTW: the tool "SoftQuadro" uses this to "convert" an Geforce into a Quadro. It tricks the driver to think that the gfx processor said "I'm Quadro" when it really said "I'm Geforce" so that the driver activates the Quadro features.

When ATI realized that what Nvidia did worked for the professional gfx market, they bought the gfx part of Diamond Multimedia to get the quite reputable "FireGL" label. First ATI continued to sell the FireGL 2/3/4 which were designed by Diamond and still consisted of discrete processors from IBM. When ATI had success with their Geforce-competition Radeon, they also decided to use the Radeon GPU for the professional gfx market. The first FireGL card that was based on a Radeon was the ATI FireGL 8800 (based on the Radeon 8500). But while Nvidia has had a very good OpenGL driver for several years already and so used the same drivers for Geforce and Quadro ATI couldn't do that. Their OpenGL drivers were aimed at Games, supported only a subset of OpenGL and also already had issues with several games (forget about OpenGL applications). So they incorporated a new OpenGL driver subset for the FireGL series.

Until some time ago I modified lots of Geforce cards to Quadros. But today I don't since Quadros and FireGLs are quite cheap now. I would never invest any time in modifying a GF2 any more. Used Quadro2 Pro cards go for sub-30EUR on ebay, and a few bucks more bring you cards like a Quadro4

500XGL which is much faster and also able to use the latest drivers. FireGL cards like the T2 are also dirt cheap now.

As to the Nvidia Geforce Go, the story is a bit difficult. Unlike the desktop GPUs for which drivers can be downloaded by Nvidia the drivers for their mobile GPUs have to come from the notebook manufacturer. Nvidia provides them with a driver development kit which they can use to create drivers for their notebooks. The same was valid with ATI btw, but ATI now supports more and more of their mobile GPUs with their Catalyst Mobility drivers. Nvidia only offers drivers for the Geforce Go 7800GTX.

Yes, it is. And a terrible one if you have to run several applications from which every one requires a different driver. But today we use the latest ForeWare drivers with all our Quadro cards. Even if they are not certified they run fine with everything.

A student doesn't need SoftQuadro. Every somewhat current Geforce card should do everything he wants just fine - without any modification (be it hardware or software). He usually can live without the Quadro features like AA lines.

To some extend, yes. Of course if you make your living out of this work I'd strongly get a certified gfx board (or better a complete system) which means FireGL or Quadro. But even there the price range is very wide today, entry level Quadro cards start at ~80EUR (Quadro NVS, mostly for 2D work) or ~160EUR for a Quadro FX 330 (3D card). ATI also starts at ~160EUR with their FireGL V3100 3D cards. There's something for almost everyone...

When I bought my HP xw8200 a comparable self-made system would have been around 150-200EUR cheaper (but also would have come without OS and 3yr onsite service). If I would have gone the RENEW path it would have been even cheaper.

Don't know about other countries but here in Germany building a workstation (means: some Opteron or XEON system, not a cheap Athlon64 gaming rig) by oneself isn't cheaper than buying a system from a reputable vendor like HP.

I only had a short look into it but it looks _very_ outdated. The GPUs which are mentioned there are all pre-2000 aera and I doubt that they are in much use today any more - especially for CAD...

But one thing to mind is that at the time this FAQ has been made there were dozens of different gfx chipsets out there, and choosing the right gfx was very difficult. Today, the majority of cards use GPUs from either Nvidia or ATI, and both manufacturers have unified drivers. It's much easier today than it had been at the time this FAQ is from...

Well, I didn't avoid this theme, I wasn't sure if I should anything to it. But ok, here I come ;-)

In short, there is basically(!) no real-world performance difference between AGP and PCIe (PCI Express). There is none in the latest super-gfx highend games, and there is none for less performance demanding tasks like CAD. So no need to throw your fast enough and well working AGP machine out to get a new PCIe system

So why PCIe?

AGP is basically an enhanced PCI bus, but unlike PCI which can have multiple devices on the bus AGP only has two (gfx card and AGP bridge in the chipset). Like PCI, AGP is a parallel bus (several parallel signal lines). AGP has been improved over the year, but still suffers from several backdraws:

- only one gfx card possible (you can't have more than one card on the AGP bus; systems like SGIs Prism which have several AGP busses need a _lot_ of technical effort for being able to do this)

- as bus performance is increased, frequency also increases which leads to increased noise and other interference radiating from the signal lines. As they run parallel, every line catches the interference from all the neighbour lines which leads to signal deformation. The second point (interference) is also a problem with PCI (and PCI-X). Another problem with PCI/PCI-X is that the bus has to be shared between all devices that connect to this bus. Depending on what cards you have PCI already is a real bottleneck.

Since it was clear that the current parallel busses have too many drawbacks that prevent them from being improved much more, something new had to be invented. And this new thing is PCIe.

PCIe is a replacement for AGP and PCI. It's not a parallel bus but consists of serial two-point connections (called "lanes") from which every lane does up to 250MB/s. To increase performance it's possible to combine several lanes 8up to 32) so that the throughput sums up. This for example is done with gfx cards. PCIe cards use a PCIe 16x connector (also called "PEG" which means "PCI Express Graphics") which uses 16 lanes to connect the gfx card to the chipset resulting in up to 4GB/s throughput. You can connect less lanes to an PCIe 16x slot (i.e. 8 lanes, like it's done by some SLI boards) which limits throughput but still works. The main advantage of PCIe is that every device has it's own connection, there is no bus to be shared over several devices which is a great improvement. And PCIe has much more room for foture enhancements than PCI and AGP.

So what does this mean for the user? Not much. If you have a good working AGP system you are not limited in performance because it's not PCIe. But you should be aware that even when PCIe has no performance advantage today(!) that this is the system of the future and that PCI and AGP are obsolete. If buying new, buying an AGP system today means locking itself out of most of the new hardware that will come out. So if you buy new go PCIe.

One note to performance: I said that today there is no performance advantage of PCIe. That is not fully true. There is no performance advantage of PCIe systems because of PCIe, but since the fastest gfx cards are only available as PCIe and since also the latest boards with fastest CPUs, memory and chipsets are also PCIe only, even today PCIe can give you more performance than any AGP system.

BTW: the same discussion (why a new standard? Why not using the older system?) happened when computers moved from ISA to VESA Localbus, then from Vesa Localbus to PCI, and it also happened when AGP was introduced. Everytime a new slot comes up, it has had no real-world performance benefit first. But even when the first AGP cards were not faster than the PCI cards of the same time, AGP fastly was mandantory because PCI got a real bottleneck. The same will happen with AGP - it's not a bottleneck today, but it will be in the future.


Reply to
Benjamin Gawert

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