View Full Version : An Idea, anybody confirm whether it is possible?

M Ragsdale
4th August 1999, 06:28
Hi all,
I was just going over the AGP 2.0 specs, and I noticed that Intel did not set aside much for allowing 2 AGP slots in one motherboard. I can see why, with the GTL bus design, there is no allowance for a separate point to point protocol other than the PCI bus and the separate AGP bus. MY thinking is that the EV6 bus (ala' K7 motherboard) allows for many point to point, thus it should be possible for TWO or more AGP cards in one system. They could set aside different banks of memory or even have memory that is dedicated for AGP texturing. Anyone have any Ideas?


5th August 1999, 16:57
It sounds reasonable to me. My concern would not be the bus/motherboard though (but firing off an e-mail to Digital/Alpha couldn't hurt. They've been using EV6 for longer than anybody else, right?). I don't really know the spec, but I wonder if the AGP cards themselves would have to be redesigned, or just have a new BIOS, to make them aware that they are not the only AGP device.
Designers have probably only considered making their video cards the only AGP device in the system. I'm sure they are designed with this concept in mind.
I wonder how useful a link between two such AGP cards would be. [PONDER] Texture exchange at the cards' memory speed, even if you only had PC133 system memory...[end PONDER]


Jon McGarry
8th August 1999, 14:42
Oooh, AGP SLI!!!

Imagine the possiblities!!!

8th August 1999, 18:34
SLI isn't really that fast. It would probably be better to split the screen in half. However, both cards would still have to do a lot of redundant calculations. Ick.

Jon McGarry
9th August 1999, 05:57
It would still be better than a single AGP card. I know that SLI PCI cards give you significant improvement over a single card.

This just goes to show how backwards Intel is. Why are they still using a 66/100 MHz bus when better alternatives have been available for a while?

Intel isn't concerned about innovating, they just want to shove their same old products down consumers throats for as long as possible.

They're still using their archaic 486 marketing scheme, which is why they blundered and allowed AMD to best them on technology.

9th August 1999, 11:26
Ick? I think otherwise, think about it, you could throw in two G400 dual heads, and run 4 monitors. Or, you could be playing a game of Q3 (or whatever turns you on), and the other card could be outputing a DVD. With an athlon system this could be entirely possible, especially since having both cards would mean you have 2 accelerated devices (4 if you have the 5.2x drivers http://forums.gagames.com/forums/wink.gif ). The possibilities are astounding. With the Point to point interconnect in the EV6 architecture, you could have dual Athlons that would be tossing any chore you throw at it aside. SLI is another possibility, imagine for a minute if the chipset or a controller on the motherboard would connect the two cards for SLI(or whatever else you have in mind to combine the performance of the two cards), then you would eliminate the sloppy pass through.

Just a thought....


10th August 1999, 02:06
I like the multi-card, multi-monitor bit. However, I don't think that SLI is the best thing anymore. After all, SLI is primarily a workaround for fillrate, isn't it? That's not nearly as much of an obstacle as it was just months/years ago. But you'd still burn up processing time doing redundant calculations. There's the ick, specific to SLI.

10th August 1999, 02:24
Hi Wombat, thanks for responding. I knew what you meant by ick. I think fillrate will become a problem again when the games start becoming more complex. Also there are probably going to be some dual Athlon systems running around doing 1Ghz per processor. CPU limitation won't be much of a problem with this type of system. Makes me tingle just thinking of a dual Ghz system. HEEHEEHEE!


Jon McGarry
10th August 1999, 08:24
I know for a fact that SLI was certainly the best alternative for Voodoo2 users. Why spend a huge sum of money for the next-gen 3D accelerator, when you could spend relatively little for what was considered another "outdated" Voodoo 2 card. The result was a 3D combination that could almost compare with the Voodoo 3. I know I haven't had any problems with Voodoo 2 SLI, and it has allowed me to skip the next-gen video cards, and save lots of money.

Certainly I think SLI will always have potential. For example, right now why not buy a TNT-2. IF they supported SLI (which they don't) wouldn't it be great in 5-6 months to buy another TNT-2 card at dirt-cheap prices and run it in SLI?? You could save lots of money, and have 3D performance comparable with next-gen chips.

Yes, I know you can't do that with TNT-2, but it was merely a hypothetical example, so don't start yelling at me.

10th August 1999, 16:37
Yes, those systems are coming (Kryotech expects to be selling a 1Ghz K7 in Nov/Dec). Do you really think that companies will come back to SLI? There has to be a better way. I don't know what it is yet, but it must be there. SLI forces the two video cards to contain the same information in their on-board memory. That seems like such a waste.
Maybe dividing the screen in half would be better, but wouldn't the cards still have to contain the same information on any polygons/textures that crossed this imaginary line?

10th August 1999, 19:47
I fail to see the point in dual AGP. Since that would need a native support from respective devices connecte to it, it makes no sense. A better solution instead of implementing dual AGP features would be to integrate 2 cards on 1 board and 1 AGP bus. And that is exatly where it's going.

And because AGP is slow even if 4x, the industry WILL go to eDRAM like Bitboys are. It's just a matter of time, and after that AGP speed makes no difference. There's plenty on mem on board which will always be faster than any AGP solution.


11th August 1999, 16:23
The point behind dual AGP is not so much multiple cards on one display, but multiple card-multiple display. Otherwise, you are correct regarding multiple-display cards. What if I want to have a G400 in one slot, and a TNT in another? I don't think we'll ever see those on the same card.
As for your second point, I think that you are completely wrong. Even with this eDRAM on board, how is the information supposed to get to the video card? Oh, I forgot, it materializes there. It still needs to be bussed in from the HD, or the system memory (the CPU isn't obsolete yet).
This could all change. After all, I've loved every Bitboyz card I've seen in the store these past few years. Oh...wait.....
I love the smell of vapor.


11th August 1999, 16:40
You just gotta love these sarcastic remarks regarding Bitboys products here.. http://forums.gagames.com/forums/smile.gif
I wouldn't worry about Glaze3D hitting the shelves 'cause Infineon (a Siemens company) has already annoused to be the one manufactoring those chips (www.infineon.com).

Anyway, dual AGP.. Hmm.. Now I got the point but I think that won't happen my man. Meaning any random couple of AGP-cards on a same mobo..
That would need a whole redesign on the mobo structure to be efficient anyway. I cannot see that happening.


Jon McGarry
11th August 1999, 23:56
I'm not talking about a random coupling of any two AGP boards, that simply won't work and would be impossible to engineer. What I am talking about is an AGP SLI situation similar to what we had with the Voodoo2. For example, any two TNT-2 cards that were close enough should work (again, merely hypothetical), but don't expect to put a Matrox G400 and a Savage 4 together. For one, it would be an insult to the Matrox card. For another the Savage 4 is a piece of crap.

12th August 1999, 05:00
Maybe intel couldn't pull it off, but why not AMD/DEC? The EV6 bus is pretty nice. As long as two slots could be supported, it wouldn't matter if they were the same make or not.

I think the other guys here have pretty much nailed it. Something Obsidian-style. Maybe. But SLI still wouldn't be as good as pure screen division. (a la video toaster).

12th August 1999, 05:28
How's this for an idea, you have two independent slots that could be used with two different cards just like you do with 2 pci vid cards; BUT you have an option in your BIOS to enable the combination of the TWO (same model of cards, with combining capable drivers). I think it would take relatively little work to implement into an EV6 motherboard, most of the work would have to come from the video card manufatures to supply the drivers to run the two in the machine together in unison. Makes you think, though.


12th August 1999, 07:39
It's a cool idea, but it would take a little more than driver support. You'd have to recombine the image, and that's a hardware problem.

Some company is already developing such a product, and had prototypes (was on the forum a while back). Essentially used the AGP slot like a 66Mhz PCI slot. Still needed to use their cards, so that the hardware could recombine the image.

Amiga had the video toaster. Those are still being used. They could run together, and actually scheduled the refresh so that each box would transmit its video signal during the appropriate part of the refresh. I understand that these vets were still being used to render the space shots in Babylon 5.