Announcement concerning the Genesi/Phoenix collaboration

[Hattig]

I would point out that the Marvell has PCI-X, which rivals AGP 8x in speed.

PCI-X at 133MHz and 64-bits is AGP 4x in speed. No great difference in the real world ... but ...

AGP is 32-bit, with 2 or 4 bits sent per clock (66MHz for 2x, 4x and 133MHz for 8x IIRC). When you put an AGP device on a PCI bus, you can only send one bit per clock. So you would be limited to AGP2x speed even with an AGP8x device ... unless you made a bridging chip, or more realistically, used an as-yet-unannounced Marvell northbridge that implements AGP instead of PCI-X.

[downix]

So you would be limited to AGP2x speed even with an AGP8x device ...

Untrue, AGP 8x devices *cannot* run at AGP 2x or lower speed.  Only AGP 4x and 8x is possible with those cards.

[Hattig]

The solutions:

1) Marvel make a northbridge with an AGP controller instead of a PCI-X controller → simple, everyone is happy

2) Genesi pay money for someone to make a PCI-X to AGP bridge chip. Costly, inefficient, higher latency, and possibly issues with full AGP compatibility. May require "August" chip to work correctly in the end.

I think the former is more likely, honestly. Then again, bbrv admitted in that thread on ANN that the Pegasos basically drives the AGP slot as a simple PCI device, without using any of the extra features of AGP. So who knows?

[JoannaK]

Well. I can't tell what they are planing to do but what I have heard about Articia-S it's AGP ain't that full-featured  either. So if they get better performance and similar compatibility than with Articias I'm quite happy.