Any PCI-Express x8 graphics cards out there?

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fibroptikl

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I am looking to get a new Shuttle system, and keep my existing graphics card (XFX 6600GT PCI-Express x16 - I don't game).

However, the shuttle I want has two PCI-Express x8 Slots. However, I can't find any x8 graphics cards. Which is weird - why are all the cards x16? From what I gather (I don't game, or follow graphics cards at all) - it will physically fit, just step down to an x8 speed.
 
I believe all PCi-E cards are backwards compatible with 8x. The speed difference is minimal or none at all.
 
no card uses 8x speed i believe so get any card that fits in the case.
 
Are you sure they dont revert to 8x when in SLI mode? My mobo does. I read somewhere there is no discernible difference between the two speeds.
 
SentToSchool said:
I believe all PCi-E cards are backwards compatible with 8x. The speed difference is minimal or none at all.
Click to expand...
Tom's Hardware did a pretty cool article recently about performance difference with different PCI-E speeds
PCI Express Scaling Analysis

image020.png


image022.png


image033.png
 
AMD_RULES said:
any x16 card will work in x8 slots
Click to expand...

I don't think this is true.

Any PCI-E card will work in a 16x slot, but you can't physically fit a 16x card into an 8x slot unless it has an open end like the original MSI nforce4 board's 4x slot picture here:



Most boards I have seen, don't use open ended slots like the 4x open ended one shown here.
 
There is no physical difference between 8x and 16x slots, the only difference is the number of lanes (8 vs 16) that the signal travels on. The 8x slot has half the bandwidth of 16, but no graphics card that is out now can max out an 8x slot, so it doesn't matter anyways. Just get a 16x card, it will work.
 
synaps3 said:
There is no physical difference between 8x and 16x slots, the only difference is the number of lanes (8 vs 16) that the signal travels on. The 8x slot has half the bandwidth of 16, but no graphics card that is out now can max out an 8x slot, so it doesn't matter anyways. Just get a 16x card, it will work.
Click to expand...

There is an obvious physical difference between an 8x slot and a 16x slot. Here is an example with this DFI board. When just looking at the PCI-E slots they are: 16x, 8x, 4x, 16x



It would be more appropriate to say that many 16x physical slots on mobos are only 8 lanes.
 
synaps3 said:
The 8x slot has half the bandwidth of 16, but no graphics card that is out now can max out an 8x slot, so it doesn't matter anyways. Just get a 16x card, it will work.
Click to expand...

That's not true. You can read the tomshardware article to see otherwise: http://www.tomshardware.com/2007/03/27/pci_express_scaling_analysis/page10.html

A 16x card will work on a 8x slot as long as you can get it seated. People with the poweredge sc430 have been modding their 8x slot so that they can put in a discreet video card.
 
metropole said:
That is interesting.

I have a x16 card laying arround (X600). Conenctors look like this:
http://images.tigerdirect.com/skuimages/large/ATI-Radeon-X600-SE-TC3H-113.jpg

It seems that there should be an addtional gap in between in order to seat it?

The motherboard:
http://photos.pcpro.co.uk/picture_library/dir_223/it_portal_pic_111852.jpg?6092
Click to expand...

That x16 card will fit in a x16 slot. It will also fit in an open-ended x8 slot as pictured in post 13 by J-Mag. It will not fit in a closed-end x8 slot (pictured in post 16).

If you have a long x8 slot with dividers (Dell uses these), see http://www.tkdan.com/SC420/ for modding details, or use a similar method to cut the end out of a short x8 slot and make it open-ended.
 
vaca232 said:
Tom's Hardware did a pretty cool article recently about performance difference with different PCI-E speeds
PCI Express Scaling Analysis

image020.png


image022.png


image033.png
Click to expand...
Toms has done a more recent article on scaling than that one. MS flight sim got hammered by the reduced bandwith, most other games had modest degredations to performance similar to what was seen in that article.
 
Kind of on the same subject, but on my DFI board I can't use the top PCI-E slot because my card blocks the SATA ports, so I had to use the bottom one which only operates at 2x or 8x depending on how you set the jumpers. I would be interested to see some performance charts comparing cards running at 8x to 16x.
 
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