Is it possible to have a pcie to agp adapter card? to put the pcie card in to agp slot?

prices for agp cards went up, but at the same time, pcie versions are still cheap.

i have pcie to pci adapter from aliexpress and everything works well, 7800,8800,9400 and even gtx480, but the pci bottleneck is making everything not so good.

It's possible to make such an adapter with PI7C9X130, but the AGP interface will be just PCI 66MHZ, with no sideband signaling.

If your Mainboard supports 66Mhz PCI Operation and you use PCIe to PCI Adapter you will gain nothing from PCIe to AGP Adapter.

sdz wrote on 2024-01-05, 08:27:

It's possible to make such an adapter with PI7C9X130, but the AGP interface will be just PCI 66MHZ, with no sideband signaling.

sdz, I've wondered, how do the higher data rates get achieved with AGPx2, x4, x8 . Can you give a quick & dirty explanation ?

I/o voltage was decreased, from 3.3V to 1.5V and 0.8V, while increasing the data rate. AGP 8x can do 8 data transfers for each clock cycle (the clock is always 66MHz).

sdz wrote on 2024-01-05, 08:56:

I/o voltage was decreased, from 3.3V to 1.5V and 0.8V, while increasing the data rate. AGP 8x can do 8 data transfers for each clock cycle (the clock is always 66MHz).

See, that's the part I don't get.
8 data transfers / clock ?
How ?

Thanks for the answer, if you have any link to reading material I can delve into, that would be great.

Maybe these can help:
https://www.dcs.ed.ac.uk/home/ecole/agp/agp10.pdf
http://esd.cs.ucr.edu/webres/agp20.pdf
https://www.playtool.com/pages/agpcompat/agp30.pdf

sdz wrote on 2024-01-05, 09:42:

Maybe these can help: https://www.dcs.ed.ac.uk/home/ecole/agp/agp10.pdf http://esd.cs.ucr.edu/webres/agp20.pdf https://www.playt […]
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Maybe these can help:
https://www.dcs.ed.ac.uk/home/ecole/agp/agp10.pdf
http://esd.cs.ucr.edu/webres/agp20.pdf
https://www.playtool.com/pages/agpcompat/agp30.pdf

Cheers !

I assembled this revision and tested it, it works fine. If anyone wants to build one, use the files provided on the previous page or download from sdz-mods.com.

One thing to mention, the adapter works fine up to at least 95MHz PCI clock speeds.

What's that adapter you have on the molex power connector?

It's a little board I made a few years back as I hate those "molex" power connectors.

This is a great use for those extra PCI-e cables on modern power supplies when used with retro systems. Do you sell these or provide a way for us to order the parts and build them ourselves?

I'll try to upload the design files tomorrow.
This PSU is designed specifically for V5 5500 AGP and PCI cards but could be used for other things, if it fits.

Thank you.

My radeon 9800 might be able to use that!

@Kahenraz
I made a page for it and uploaded the files : http://sdz-mods.com/index.php/2024/01/27/v5-5 … 00-agp-pci-psu/
Gerbers, as well as sch/pcb, so one could modify it if needed.

This is wonderful. Thank you.

You're welcome!

agp to pci adapters without pci-pci bridge are limited in their functionality. win9x won't work, older mobos won't work. just because they don't expect a pci card with idsel tied to ad16 as agp cards have.

sdz wrote on 2024-01-04, 13:29:

Time to necropost... […]
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Time to necropost...

I finally got to finishing the new revision of the adapter, I have uploaded it here:
http://sdz-mods.com/index.php/2020/06/22/pci-to-agp-adapter/
Editable schematic & board file, PDF schematic, BOM, and GERBER files.

Hi SDZ,

Could you share the files for the PCIe x4 to PCI 66Mhz bridge as well?