X1 PCI-E card in X16 slot???

[maverick77_uk]

Hi all,

I've just read this hexus article:

http://www.hexus.net/content/item.php?item=6118&page=1

In it, they test a new graphics card from HIS thats operates on a x1 PCI-E interface. However, because the MoBo they use only turns off on-board gfx when a card is in the x16 PCI-E slot, they whack it in there. Can you do that?

Is it OK to plug x1 devices into x16 slot? Can yo do they same (in theory) to x2, 4 and 8 slots?

How can you be sure the connectors are lined up properly? surely the point is to have the card connector and slot the same size to ensure a snug fit?!?!

Thanks for your input!

[shaithis]

PCI-E slots are all backwards compatible.

I am pretty sure that the reverse is theorically possible as well, you could hack a peice of a PCI-E connector off and get a 4x card working in a 1x slot of example.....

[-ChEM-]

no that wont work

the data is split into lanes out along the length of the card so to use a wider card in narrow slow you have to use an adapter, otherwise with say an x4 card in an x1 you will only get 1/4 of the data the card is trying to send (well you wont get anything because the computer probably wont start)

but if you get an adapter i think its fairly easy to merge the 4 lanes back into 1 as the pin layout follows a nice regular pattern of the same pins in sequence

[FatalSaviour]

I thought I saw an article a year or two back where they taped off a quarter, and then half of the pins, and the card continued to work.
This of course involved a 16x card being made to look like a 1x card, and then plugged into a 16x slot, but not sure how dynamic allocation of PCI Express lanes on the mobo works exactly.
Not that I would want to hack off half of the connectors on my £400 graphics card

[-ChEM-]

maybe youre right, i would be happy if that was true with this stupid x1 slot i have free

[ajones]

I thought I saw an article a year or two back where they taped off a quarter, and then half of the pins, and the card continued to work.
This of course involved a 16x card being made to look like a 1x card, and then plugged into a 16x slot, but not sure how dynamic allocation of PCI Express lanes on the mobo works exactly.

Aye.. I remember this article too. Think they were comparing various PCI-Ex configurations against AGP to see if the extra theoretical throughput made much of a difference.

I'm guessing that the PCI-Ex bus controller can work out which channels are electrically connected and therefore will only send data along those. I doubt there's any control protocol between the PCI-Ex device and controller to specificaaly request a certain number of channels.

[GoNz0]

i wish they would make a X-Fi card fit a PCI-Ex4 slot so i dont have to stick it between my 7900gtx's

[shaithis]

Creative are currently re-designing their sound chip from scratch due to it having numerous issues when they tried to mount it on a PCI-E bus...

Going to be a while before we see a decent PCI-E sound card I feel

[FatalSaviour]

It's got numerous issues on the damn PCI bus, let alone the PCIe!
I'm waiting for a driver release to fix these crackles...but no luck so far

[GoNz0]

i dont think there will be a fix, creative have always had that problem, and each new series of soundcard seems to have that bug on certain setups.

its also never really been fixed on there older cards, so can't see them fixing it now

[shaithis]

Had that crackle with a SB Live in a VERY old KT7 mobo......never had the problem since.

There is a PCI Latency fix floating around the net somewhere that may help with it, I used it on the aforementioned mobo with some success.