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Adding more pci slots

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First post, by Sphere478

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Is there something like this that allows like four more pci slots?

Available connections on motherboard are pci, isa.
I do have a pci to usb3.0 and a pci to pci express card but I was hoping for a more native option like pictured that had more slots. I suppose I could try stringing a few together but... eh. Idono if that’s the best approach 🤣

Also, do you think making the cables longer would work with what I have?

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Last edited by Sphere478 on 2021-01-21, 23:49. Edited 1 time in total.

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Reply 1 of 29, by The Serpent Rider

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Chipset has finite number of PCI slots available, usually only 6. Expanding it further will require PCI-PCI bridge.

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Reply 2 of 29, by Sphere478

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The Serpent Rider wrote on 2021-01-21, 23:38:

Chipset has finite number of PCI slots available, usually only 6. Expanding it further will require PCI-PCI bridge.

It’s a 430tx chipset. How many on that?

So, this is just basically uncovering another pci slot that was never installed right? Most of the traces are in parallel except like a interrupt lane or something right? Each slot gets it’s own one of those? Or am I totally misunderstanding how this works?

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Reply 3 of 29, by The Serpent Rider

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AFAIK no, you can't connect PCI like that. This will result in conflict when two cards are connected, so PCI bridge is required.

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Reply 4 of 29, by matze79

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And it will make a nice antenna

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Reply 5 of 29, by Sphere478

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The Serpent Rider wrote on 2021-01-22, 00:02:

AFAIK no, you can't connect PCI like that. This will result in conflict when two cards are connected, so PCI bridge is required.

Looking at the riser now. It does seem to have some kind of chip between

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Reply 7 of 29, by chrismeyer6

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What you want to do works for ISA but you'll be hard pressed to get it functioning properly with pci. You'll probably just end up with hardware conflicts and those extender cables act like antennas and will cause noise on the pci lanes.

Reply 8 of 29, by darry

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Sphere478 wrote on 2021-01-22, 02:34:
The Serpent Rider wrote on 2021-01-22, 00:02:

AFAIK no, you can't connect PCI like that. This will result in conflict when two cards are connected, so PCI bridge is required.

Looking at the riser now. It does seem to have some kind of chip between

That chip is very unlikely to be the required PCI bridge chip (EDIT: or maybe it is or, more likely, that photo shows only part of what is needed and the actual bridge chip is on the host PCI card).

To properly and safely expand a PCI bus, you need to use an expansion chassis with a PCI bridge chip , like this, for example https://www.onestopsystems.com/product/13-slot-pci-expansion (probably overkill for your needs). EDIT: Cheap and reliable PCI and PCI Express chassis for PCI Express slots do exist (and use a bridge chip) . I have one . No idea if you can use an additional PCI to PCI Express bridged adapter with one of those .

As mentioned before, expanding a PCI bus is a lot more complex than doing the same for ISA . I am not an expert at PCI, so more knowledgeable people can correct me if necessary, but I am pretty convinced that wedging one of those passive PCI backplane expanders in a random PCI slot will not work .

Reply 9 of 29, by matze79

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Its possible but not worth the Effort Specially if you expand a Old System with only a few IRQs its not worth all the Troubles.

There Industrial PCI Card where a Cable can connected to a Box with additional PCI Slot.
They contain Driver ICs, PCI to PCI Bridge and additional Power Supply.

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Reply 10 of 29, by Sphere478

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I plugged that adapter into one of my computers and plugged two cards into it and it seemed to work fine.

That server rack is cool but way more than I need. Is there a smaller solution?

I could buy a bunch of these smaller cards I guess. But that’s kinda a weird setup and they are hard to mount with such short cables

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Reply 12 of 29, by wiretap

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I use the same riser in my ITX Voodoo 2 SLI machine. It is a passive bridge, nothing shows up in my device manager. The chip on that bridge is just for clock arbitration I believe.

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Reply 13 of 29, by darry

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wiretap wrote on 2021-01-22, 16:45:

I use the same riser in my ITX Voodoo 2 SLI machine. It is a passive bridge, nothing shows up in my device manager. The chip on that bridge is just for clock arbitration I believe.

So that bridgeless riser actually works with 2 PCI cards in it while being installed in an ordinary PCI slot ?

Reply 15 of 29, by The Serpent Rider

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I thought about two Voodoo 2 working with such riser, but had some doubts after looking at Quantum3D designs, which all included additional controller for SLI boards like Obsidian X-24.

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Reply 16 of 29, by Sphere478

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chrismeyer6 wrote on 2021-01-22, 16:30:

Just curious with that riser card installed in the device manager does it show a new PCI to PCI bridge?

I forgot to look. My suspicion is no but I will look next time. It took a while to set up

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Reply 17 of 29, by wiretap

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The Serpent Rider wrote on 2021-01-22, 18:22:

I thought about two Voodoo 2 working with such riser, but had some doubts after looking at Quantum3D designs, which all included additional controller for SLI boards like Obsidian X-24.

Two Voodoo 2's work fine. I've been using it, and it works as expected. Benchmarks are the same as two native PCI slots.

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Reply 19 of 29, by wiretap

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There's really not much airflow except for the window vents on the case. I may add a fan at some point, but it doesn't concern me since I don't use the machine a whole lot. The only fan in the system is inside the power supply. Maybe if I feel like being adventureous I'll mod it, but as it stands the RVZ02 case does not have any fan mounting locations.

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