Pegasos II and graphics cards

[Rob]

As I understand the Pegasos II will be using the Discovery II
northbridge from Marvell.
On Marvell's website the specs include PCIX but the is no mention of
AGP, which rather suggests that there will be no AGP for Pegasos II.
Am I correct here?  If so, what will all the Pegasos I owners who
upgrade do with their AGP cards.

[KennyR]

Pegasos 2 will have AGP.

[zacman]

>Am I correct here?

There are many speculations about the specs of the
Pegasos2. But besides the info that it will support
gigabit ethernet and DDR ram nothing else had been
officially said about the features yet.

So just wait for the final announcement.

[MarkTime]

I asked about this early on, and they said it will support AGP.

64bit 66mhz PCI is AGP equivalent, in terms of throughput, but you find AGP cards on the market, and not many 64bit 66mhz PCI graphics cards, so they would need to do some hardwdare implementation to give you a physcial AGP slot, as well as whatever else they need to interface that to the marvell.

my assumption is, whatever AGP slot they develop, it will be a 2xAGP slot equivalent (that wouldn't stop someone from supporting higher multipliers, just wouldn't get any more throughput than the marvell can handle)

but, I'm no hardware engineer, and people can correct me at will.  Just my thoughts.

[takemehomegrandma]

@ Rob

Not much is known about the Pegasos II specifications, but one
of the few things that IS known is that *it will have* AGP (of
course!). AFAIK, AGP in Pegasos II will be implemented pretty
much the same way as in A1/Pegasos I.

[Rob]

If they can interface an AGP port to the PCIX bus will this mean
support for AGPX4/8.

[Dr_Bombcrater]

MarkTime wrote:
I asked about this early on, and they said it will support AGP.

I hope so, but it's going to be hard. The Marvell 6436x series do not have any support for AGP.

64bit 66mhz PCI is AGP equivalent, in terms of throughput but you find AGP cards on the market, and not many 64bit 66mhz PCI graphics cards,

If such cards exist the demand for them must be vanishingly small. How many systems implement a 64-bit 66MHz PCI slot and don't have AGP?

No doubt they'd cost for more than the Peg2 itself, and whatever chipset they use would be well out of date.

Apple has used 32-bit 66MHz cards in the past, but I don't know if these are available on the open market.

so they would need to do some hardwdare implementation to give you a physcial AGP slot, as well as whatever else they need to interface that to the marvell.

And that's where the difficulty lies. The only real way to do this is to build an AGP-PCIX bridge chip, but that way is fraught with serious problems. AGP supports things like sidebanding and isosochrinous transfers, that the PCI bus cannot support. There's also issues like voltage conversion, becuase PCI is 3.3v and the latest AGP cards are 1.5v, and saturation of the PCI bus by AGP traffic.

The old 'Socket 7' PC chipsets used this approach to kludge AGP into an architecture that didn't support it, and anyone who's had to deal with such systems knows how poorly that worked.

my assumption is, whatever AGP slot they develop, it will be a 2xAGP slot equivalent (that wouldn't stop someone from supporting higher multipliers, just wouldn't get any more throughput than the marvell can handle)

I think the only hope of getting real, reliable AGP onto the Peg2 is if someone has developed a PCIX-Hypertransport bridge. Putting Hypertransport in there would allow to designers to use one of the AMD, VIA or nVidia AGP controllers that have been designed to work with Opteron and Athlon64 systems.

## Doc

[takemehomegrandma]

Dr_Bombcrater wrote:

I hope so, but it's going to be hard.

Not at all!

The Marvell 6436x series do not have any support for AGP.

Not that unusual actually. But this is something that concerns only the mobo designers and it's nothing the end-users needs to think about.

64bit 66mhz PCI is AGP equivalent, in terms of throughput but you find AGP cards on the market, and not many 64bit 66mhz PCI graphics cards,

If such cards exist the demand for them must be vanishingly small. How many systems implement a 64-bit 66MHz PCI slot and don't have AGP?

AFAIK, neither will the Pegasos II. AFAIK, it will not have 64-bit 66MHz, but it will definitely have AGP.

[Dr_Bombcrater]

takemehomegrandma wrote:

The Marvell 6436x series do not have any support for AGP.

Not that unusual actually. But this is something that concerns only the mobo designers and it's nothing the end-users needs to think about.

I don't think you realise the scale of the problem here. AGP support is a function of the North Bridge chip. If the North Bridge lacks that ability then it becomes almost impossible to add AGP. At best it will be difficult, expensive and slow.

I'd like to pose a simple question here: name me one motherboard (any platform or architecture) that has an AGP slot without North Bridge AGP support.

AFAIK, neither will the Pegasos II. AFAIK, it will not have 64-bit 66MHz, but it will definitely have AGP.

Don't hold your breath waiting. The only way Genesi are going to get AGP ont the Peg2, especially at the very aggresive price points they've announced, is to dump the Marvell North Bridge and go with the MAI Articia P, which has built-in AGP capability.

## Doc

[KennyR]

Well, Articia-P is not an option. Not only will Genesi shy from trusting Mai again, but adopting the Articia-P would set the Pegasos back many months.

I'll wait until the Pegasos 2 is ready to see what kind of AGP it has. Releasing it with none would be crazy. People would simply not buy it (including me), and who still makes PCI cards in this day and age?

So for this reason, AGP with Marvell is really a Do or Die measure for Genesi. Whether they'll manage it or not will be interesting to see, but they've never fallen short in the hardware ingenuity stakes before.