Like this one? Re: AGP to PCI adapters - any PCB designers here willing to make one?

EDIT: That link was for pci to agp. But I guess pci-express to agp should also be possible because many late agp cards were already pcie designs with bridge chips: https://www.anandtech.com/show/1545

janih wrote on 2021-10-28, 06:18:

Like this one? Re: AGP to PCI adapters - any PCB designers here willing to make one?

EDIT: That link was for pci to agp. But I guess pci-express to agp should also be possible because many late agp cards were already pcie designs with bridge chips: https://www.anandtech.com/show/1545

https://images.anandtech.com/reviews/video/NV … TAGP/bridge.jpg

Ooo yeah, like with this chip except have it give me a 16x slot on my old motherboard.. 🤔

pretty certain sdz has a working one... though haven't seen a lot of him recently. Must be busy.

Hello,

I have developed this one adapter AGPtoPCIe but only compatible for VGA 3.3v- specially for 3dfx Cards.

Regards,
Oscar.

I believe this thread is about a converter that will allow a PCIe GPU to work on an AGP motherboard.
A converter that will connect into an AGP slot and provide a PCIe slot.
Maybe the OP and title should be changed to be more specific.

I made (GPU-MB) AGP-PCI, AGP-PCIe, PCI-PCIe, adapters. The PCIe ones are x4 and can overclock the PCI/AGP interface. I will open source all of them at some point. I design hardware for a living and this year was a nightmare due to the IC shortages, I Iiterally have no time to work on these at the moment (they are all working, but I need to optimize the BOM and check everything again, as I designed these quite some time ago). They aren't even manufacturable at the moment, some of the ICs used on these adapters are unobtanium since february or so.
As for an adapter than can allow a PCIe video card to work in an AGP MB, it can be done, but personally I don't see the point.

Is it possible? Yes, Nvidia adapted some AGP cards to PCIe with HSI bridge. GeFofce PCX 5300, GeForce PCX 5750, GeForce PCX 5900, GeForce 6800GT, GeForce 6800 Ultra.
Can you make one today, which can be fully functional AGP? Not really. Not only you need to make AGP-PCIe bridge from scratch, but you also need GPU driver which is aware of such bridge and can translate specific AGP calls to PCIe.

EDIT: Making adapter which will function as PCI 66 MHz is relatively easy though, but performance will drop noticeably in some games.

@The Serpent Rider
You are correct, what can be done today is PCIe GPU to AGP, with no AGP features, basically PCI@66MHz via the AGP connector.

sdz wrote on 2021-10-28, 09:12:

@The Serpent Rider
You are correct, what can be done today is PCIe GPU to AGP, with no AGP features, basically PCI@66MHz via the AGP connector.

How does it deal with the data path being 64bit on agp?

rmay635703 wrote on 2021-10-28, 13:30:

sdz wrote on 2021-10-28, 09:12:

@The Serpent Rider
You are correct, what can be done today is PCIe GPU to AGP, with no AGP features, basically PCI@66MHz via the AGP connector.

How does it deal with the data path being 64bit on agp?

Isn't it 32bit?

Doornkaat wrote on 2021-10-28, 14:57:

rmay635703 wrote on 2021-10-28, 13:30:

sdz wrote on 2021-10-28, 09:12:

@The Serpent Rider
You are correct, what can be done today is PCIe GPU to AGP, with no AGP features, basically PCI@66MHz via the AGP connector.

How does it deal with the data path being 64bit on agp?

Isn't it 32bit?

Looking at the pinout I would have to say, It is 32bit.

osckhar wrote on 2021-10-28, 09:00:

Hello, […]
Show full quote

Hello,

I have developed this one adapter AGPtoPCIe but only compatible for VGA 3.3v- specially for 3dfx Cards.

Regards,
Oscar.

I was talking about going the other way.

Doornkaat wrote on 2021-10-28, 09:04:

I believe this thread is about a converter that will allow a PCIe GPU to work on an AGP motherboard.
A converter that will connect into an AGP slot and provide a PCIe slot.
Maybe the OP and title should be changed to be more specific.

Yes this, I’ve searched but didn’t find? Any help with link?

sdz wrote on 2021-10-28, 09:12:

@The Serpent Rider
You are correct, what can be done today is PCIe GPU to AGP, with no AGP features, basically PCI@66MHz via the AGP connector.

Did you ever send that AGP-PCI adapter onwards ?

Sphere478 wrote on 2021-10-28, 15:46:

Doornkaat wrote on 2021-10-28, 09:04:

I believe this thread is about a converter that will allow a PCIe GPU to work on an AGP motherboard.
A converter that will connect into an AGP slot and provide a PCIe slot.
Maybe the OP and title should be changed to be more specific.

Yes this, I’ve searched but didn’t find? Any help with link?

Sorry, but I don't know any. I was just trying to help clear up the confusion.