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The "Not Quite Amiga but still computer related category" => Alternative Operating Systems => Topic started by: RMK305 on December 20, 2008, 03:30:52 PM

Title: Can I use a PCI Express 2 card in a PCI express 1 slot?
Post by: RMK305 on December 20, 2008, 03:30:52 PM
As the title says, can I use a PCI express 2 graphics card on my PC which has a PCI express 1 slot? The card in question is the ATI 4870. A friend is talking about getting one for their son for christmas and has asked me to look into what the options were.

Thanks,

Robert
Title: Re: Can I use a PCI Express 2 card in a PCI express 1 slot?
Post by: mikedouble on December 20, 2008, 03:37:33 PM
I believe it is backwards compatible both ways, and Wikipedia seems to say the same thing...

http://en.wikipedia.org/wiki/PCI_Express#PCI_Express_2.0

Mike
Title: Re: Can I use a PCI Express 2 card in a PCI express 1 slot?
Post by: carvedeye on December 20, 2008, 07:51:55 PM
that answer is simple ....YES.
Title: Re: Can I use a PCI Express 2 card in a PCI express 1 slot?
Post by: RMK305 on December 20, 2008, 08:32:35 PM
Thank you both very much.
Title: Re: Can I use a PCI Express 2 card in a PCI express 1 slot?
Post by: alexh on December 20, 2008, 08:49:00 PM
Some cards are not physically backwards compatible from a lanes point of view.

i.e. you cannot put a 16x lane card in a 1x lane slot
Title: Re: Can I use a PCI Express 2 card in a PCI express 1 slot?
Post by: RMK305 on December 21, 2008, 08:16:24 PM
The slot is a 16x and the card is a PCIe 2.0 x16 so it should be good. Thanks.
Title: Re: Can I use a PCI Express 2 card in a PCI express 1 slot?
Post by: darksun9210 on December 22, 2008, 08:49:26 AM
you can put a 16x card in a 1x slot. you just need to either cut a groove in the end of the slot. or, snap the end off of the slot with a flatbladed screwdriver and a hammer.
(for those of you who don't care, or who have someone who really really wants another GFX card in there no matter what - been there, done it, and it works.)

some 4x slots actually have a groove in the end to take 8x and 16x cards already, like on my gigabyte G33 board.

all PCI express cards fit all PCI express slots. just a little physical adjustment might have to be made. just dont expect a 16x card to work at 16x in a 4x slot, as it will only be able to use the PCI express lanes available in the slot.

you can experiment with this with a 16x card in a 16x slot, and taping up the pins on the card so that they don't make contact after looking at a PCI express pin out diagram like this one (http://pinouts.ru/Slots/pci_express_pinout.shtml)
to reduce the number of lanes available.

and yes you can put a v1 card in a v2 slot, and a v2 card in a v1 slot. the only difference is timing. but then the v2 spec of PCI express for both card and board slot, is that they are able to accept v1 timing as well.

--disclaimer--
i take no responsability for any damage that might occur from you taking a metal stick with an edged end (say, a large flat bladed screwdriver, or chisel), and percussive energy emitter (say, a wooden mallet) to the motherboard of a machine.
information provided purely "as is" and on no account to be acted apon unless you are able to take full responsability for your actions after properly researching what you may or may not be about to undertake.