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Other Uses for an AGP Slot?
SleepyHappyDoc asks: "AGP seems to be going the way of the dinosaur, but there's still a lot of slots on legacy motherboards out there. If you don't have need for the graphical advantages of AGP (say, on a headless server), what else could you use the AGP slot for? Could the advantages of AGP over PCI be leveraged in a use other than graphics cards?"
I would think that perhaps you could use the bus bandwidth and an old/slow card to do additional computation. Leverage the GPUs in the more recent AGP 3D offerings and use it for something...uh....usefull :)
Perhaps we can user in a new age of game design where you can load your machine up with older cards to assist with the heavy 3D math for a game, or maybe expose those cards as a virtual machine of some sort.
Blar.
I'm going to have to go with none and move along.
The problem with slashdot is that most of its users were bullied and stuffed into lockers as kids!
http://www.matrox.com/mga/theguide/contents/AGPvsP CI.cfm
There are places where the networks are not touching,and there are places where they are-Boeing's Lori Gunter
AGP has more downstream bandwidth to the slot than upstream bandwidth from the slot, whereas PCI and PCIe have the same to and from the slot.
You could use it for something like a beefy sound board.. or, something...
No, not much other than graphics output really needs that kind of bandwidth differential.
I don't know of any non-gfx cards that would use the CPU but there was a C compiler released that would use the GPU instead of CPU for your generic computations (instead of 3d gfx) and for certain kinds of calculations/programs it would be equivalent of 10GHZ P4 class CPU in the means of speed. Look up archives of Slashdot for it.
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Well, this still involves to use a graphics card, but in a bit different way.
YMMV with the performance though.
while true; do eject; eject -t; done
AGP is a one-way architecture - the motherboard sends data to the graphics card, the graphics card processes it and sends it to the monitor. The limitations of this way of working are why dual graphics card solutions were never practical on AGP once you started increasing the complexity of the data - the bus wasn't capable enough.
That said, it's not impossible to get it working. You just need to get around the one-way bus problem. There are two obvious solutions for this, to my mind: (ignoring the fact that no cards exist to do it for you)
Use it for one way data
You create a card that acts only to process and send away data. At its simplest, this might be an audio card (without line-in, obviously). Getting slightly more creative, the card could take the 'load' of preparing documents and printing them off the CPU, although I can't see this being useful. Using a rather crossfire-like setup, you could send the output of a suitable graphics card into an input on another, and use it as a pre-processor; at its most basic this could be used to divide a signal in half to be processed by two (or more) cards, or getting more complex it could render something simple - perhaps hidden windows, for use in transparency effects, or perhaps acting as a 2D processor and leaving 3D work to the 'bigger' card - tag this as 'rendered' and send the output to its big brother.To be honest though, this seems a little ridiculous.
Creating a feedback path for 2-way data
This, in my opinion, is where it could be useful. The moment you add a way to send data back - at its simplest, I suppose this would be a SATA or IDE cable and suitable software that continuously reads the contents of the 'hard disk' - you have an opportunity for a specialised processor. The hack would be incredible difficult, granted, but the processor on a graphics card would seem to be well suited to encode video. You send your stream to the AGP card, it converts it to mpeg4 (for example) and sends it back via SATA, taking 99% of the load off the processor. (These cards have recently started to appear for PCIe, so the is definitely a market). With some sort of feedback path, the card could do anything a PCI card can do, but substantially faster thanks to AGP's higher bandwidth - the trick is getting a decent feedback loop.
After all that, though, I think the practical answer is no, there is no use for an AGP slot other than graphics; there is no demand for other cards, so they just don't exist.
GPGPU is what you're looking for.
bidi is not everything. If you have a 33k modem connection to a 256-node beowulf cluster, do you claim it's useless? AGP cards have pretty beefy serial processing chips, that can be programmed with any, generic tasks just like CPUs, and for some of these tasks they will suck a big time (but still work) and for some they will rule (stuff like lots of similar rather simple calculations on lots and lots of data - they are unbeatable.) Statistics, rendering, filtering, encoding/decoding, all such stuff is really fast. Now the downstream is pretty slow so it hurts that -very- simple calculations can't be done en masse (the GPU can do them great but they get stuck at sending them back to the PC), and hard calculations with lots of decision-making are better handled in the CPU but there is a class of tasks where the GPU is unbeatable.
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Leverage is not a verb. Please stop using it as such. See the article posted today about loss of literacy.
-Splat
As it is write only, it is ideal for implementing a hardware /dev/null on Unix systems.
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So how would propose I add another gig when it cannot even accept a single gig?
It does however have a 32mb graphics card that is not used. Oh sure it is a tiny amount of memory but when the kernel is forced to start swapping it makes a difference. Not a huge amount to be sure and it doesn't help at all when it really needs to swap a lot but it gives me just a little bit more room to play with.
Haven't thought about upgrading the card but I guess if I ever see a really cheap 256mb card it might be worth it.
A dual P3 is still plenty fast for desktop use especially since the linux kernel keeps on improving. Windows users may wish to close their ears to save themselve from terminal shock but linux installs get better with age.
Sure sure someday I am going to have to buy a new system and now that dual core chips are here the hurdle is not as big as having to buy a dual single core machine was but still, the longer I can keep this system running the happier I am
Hardware/software hacking is about making stuff go that extra mile. Just plonking a wad of cash on the counter is totally missing the point.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
I don't think you guys understand the kind of massive speed differential we're talking about. I don't remember the numbers, but it's like G/s to the card and K/s back. It's just enough to tell the processor that the card is ready for the next rendering task, nothing more.
Someone mentioned doing video compression... because you could send the compressed file back. Well ok, except, A. video cards only have 256mb of ram... so your uncompressed video would only be like what 30 seconds? B. getting the data back to the hard drive would be like transfering files over a serial cable... like old PS/2 serial, not USB2 serial.
Now... a card with a SATA out would work. That's the kind of bandwidth that would help, although for most applications just an IDE out would do the trick.
But these cards don't exist. So no... nothing to be done with agp slots.
Where do all these other top-level posters get their information?
w ww.gcsextreme.com/agpfaq.htm for more info. (Sorry, Slashdot's code doesn't want to let me make that into a proper link, it breaks it into 'archive.org' and 'gcsextreme.com' segments, you'll have to copy and paste, then remove the space yourself.)
AGP is a subset of PCI. The original AGP spec (1.0) defined a dedicated slot with a 32-bit, 66 MHz PCI connection directly to the Northbridge, plus the ability to directly access main memory more quickly than conventional DMA allowed. AGP 2x then increased speed by using a double data rate system, similar to DDR memory, transferring two data chunks per clock cycle.
AGP 4x then added a quad data rate connection, Fast Writes (the ability to write to main memory out of normal order,) and Direct Memory Execute (the ability for the AGP card to execute directly out of main memory, rather than having to load into on-board memory first.)
AGP 8x just oct-data rate'd it. It's still 32-bit, 66 MHz PCI, though.
But, either way, AGP *IS* a PCI connection. Fully compliant with PCI 2.1, with full bandwidth in each direction.
There are/were bridge chips that converted the AGP connection into one or more PCI slots, which would become fully-compliant PCI 32-bit, 66 MHz slots. These bridge chips were sometimes used on lower-end server motherboards with onboard PCI video, as a cheaper alternative to adding a separate 64-bit PCI controller. They could be found on products from Intel (L440GX,) and others.
BUT, since it is only 32-bit, you're limited to a 32-bit, 66 MHz PCI connection. PCI-X requires 64-bit for its faster bus speeds. That means that there are no bridge chips that will give you anything better than a 32-bit, 66 MHz PCI 2.1 connection. You can run multiple cards off this connection (As the Intel board listed above did,) but just as with 'regular' PCI, you are sharing the speed among all the cards.
But, any 66 MHz PCI card (or any correctly backwards-compatible PCI-X card,) would take advantage of the doubled speed over 33 MHz PCI, though.
See http://web.archive.org/web/20040205095311/http://
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