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Is it possible to convert a PCI-e x1 slot into an old PCI slot? If so, how?

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Some additional information might help you make the best choice. What card are you trying to use in a pci-e slot? There may be a replacement or upgrade that your money would be better spent on. – Troggy Sep 25 '09 at 20:24

No, this is not possible. I have never seen a product for that purpose and I am not sure how they could do it. Pci-e slots(not even the full size 16x versions, let alone a 1x) are not backwards compatible with pci.

Edit: People are finding solutions for this. I do however agree they are not that cheap, add complexity (drivers, overhead, etc), and some of these adapters I am seeing will only work with low profile cards. I know some of these adapters will not work with all cases. You might have to remove the case mount plate on the PCI card to be able to use. If it is a full height PCI card, you might be stuck in many cases, unless you do not mind the side of your case being off.

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Motherboard expansion slots are designed to line the card up with the back of the case. So even if an adapter was somehow produced, I am not sure how they would fit an adapter and the card properly. None the less, good question. – Troggy Sep 25 '09 at 18:58
Sorry, they actually do exist...I should have done my homework before i asked, my bad. – Faken Sep 25 '09 at 19:10
Wow, I didn't realize anyone had attempted this. You learn something new every day. Haha. – Troggy Sep 25 '09 at 19:33
Added some relevant info in light of new findings. – Troggy Sep 25 '09 at 19:42
Yea, they are damn expensive...oh well at least I'm not paying for it. Ill probably get one of those quad box things, in case i need even more slots. This actually works out quite nice as i wont be needing those slots for quite some time, this means i can squeeze more money into the computer budget itself to get a more powerful computer and buy the converter box later as some other expense (i don't like it when the computer can't keep up with me) – Faken Sep 26 '09 at 18:24
up vote 5 down vote accepted

Well after a little digging around (which I guess i should have done first) the truth of the matter is, yes, there actually are. There are little cards that you can slip into the PCI-e x1 slot to convert it to a PCI slot. Why would anyone want to do this you ask? well, many companies still make products intended for PCI slots, not PCI-e. It was the graphics card companies that lead the rush twords PCI-e (and for some very valid reasons).

However, new interfaces take time to get accepted, besides, if an old standard works perfectly fine, development of the product to switch to a new standard would be extra costs.

Unfortunately most computer motherboard manufacturers seem to want to follow the rush twords new technology even when older technology still works fine. What i don't understand is why do computer motherboard manufactures even put PCI-e x1 card slots in their systems. At the moment, the only technology that uses PCI-e slots is either graphics cards, raid controllers, or USB2.0. As far as graphics cards go, the PCI-e x16 slot is a necessary advancement. However, no one buys raid controllers because most people who use it have raid chips inside their motherboards anyways, this goes the same with USB2.0.

So whats the point of having PCI-e x1, x4, and x8 slots if they are rarely used? Instead of a useless PCI-e x1 slot, why not put in a useful PCI slot insted?

PCI-e x1 to PCI converters:

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They make Ethernet cards, wireless cards, adapters etc. also. There is much more out there than just graphics, raid, and usb. – Troggy Sep 25 '09 at 20:29
The reason mobo makers like PCIe 1.x slots is that they're cheaper to implement. They only need 18 pins vs 62 for a 32bit PCI slot. Fewer traces leads to simpler board layout, less EMI, and potentially fewer layers needed in the PCB itself (this is a big cost savings). – Dan Neely Jan 25 '10 at 15:59
Makers of low end expansion cards also like the form factor since it reduces the minimum size of the PCB needed for the card. If you look on sites like newegg you'll see lots of a triangle and L shaped PCI cards that add an ethernet port/usb ports or something else that's trivial and which needed to make the PCB larger to support the connection to the mainboard. – Dan Neely Jan 25 '10 at 16:01
For devices that can consume significant amounts of bandwidth PCIe is also better since a 1x slot gives either 125 (1.0) or 250MB/sec (2.0) of dedicated bandwidth in each direction, vs PCIs 133MB that's shared both directions with all other PCI devices. In the next year or so PCIe 3.0 will boost the per lane bandwidth to 500MB/sec allowing SATA6GB and USB3 addon cards to operate at near full speed in a 1x slot. – Dan Neely Jan 25 '10 at 16:03
Also, "RAID" chips on motherboards are almost never real RAID--they're software fakeraid. Real RAID cards generally have backup batteries. – Broam Feb 19 '10 at 15:39

PCIe-to-PCI converters exist, but they are rather expensive and add another layer of complexity to a computer's setup.

It's generally cheaper to purchase a new expansion card that is PCIe rather than attempting to fiddle with a converter.

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Assuming that you're actually trying to plug a PCIe card to your desktop...

Double check your motherboard's manual. Sometimes you can plug a PCIe x1 board to a slot that is PCIe but more lanes than x1.

If you're trying to plug a PCI card on to a PCIe slot, that's quite different. You can probably still find a PCI to PCIe bridge somewhere, but it's not worth your while.

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this don't help much if he got a reqular PCI card – Joakim Elofsson Sep 25 '09 at 19:49
Yah, this doesn't answer any part of the question. – Troggy Sep 25 '09 at 20:14
I actually wrote that thinking that he wants to convert a PCIe card into a PCI. If that's the case, the OP could be just looking for the right slot to put his PCIe card. However, if he's looking for a PCIe slot, to convert to a PCI slot, then he's probably just out of PCI slots. – calyth Sep 25 '09 at 20:32
Actually, im trying to buy a powerful budget computer for use at the university. I found the exact PC i wanted at dell with a very reasonable price, the only problem is that it only comes with 1 PCI slot and a whole whack of PCI-e x1 and x4's which are total useless. We cant swap out the motherboard to get more PCI slots. Thats why i was looking for something like this so i can plug in more PCI slots. I'm doing some robotics control and i need 2 PCI slots for motor controler boards. – Faken Sep 26 '09 at 18:09
@Faken Last I read about hardware bridges were for graphics card, bridging a chipset in PCIe to AGP (or the other way around). It doesn't require drivers, but it introduce another item for things to cause problems. A 2 PCI slot board is abundant. And you shouldn't blow through your budget unless you're getting an i7. Is your program single-threaded? or multi-threaded? i.e. is it cranking at a tedious task that can't be broken apart? or is it busy juggling tasks? – calyth Oct 1 '09 at 20:32

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