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Video card PCI-E 16x in a PCI-E 4x slot ????

Last response: in Graphics & Displays
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April 16, 2006 7:53:40 AM

2 weeks ago my motherboard (ASUS P4PE AGP-4x) and my video card (Leadtek 6800GT AGP-8X) was broken.

I'm happy with my RAM (2x512MB DDR400) and CPU (P4 3.06GHz HT 478pin) so I've replaced my old motherboard with a ASUS P4V800D-X (based on VIA PT880Ultra and VIA 8237R).
This new mobo support my old CPU and RAM and has one AGP-8x slot and one PCI-E 16x slot but running ad 4x speed max.
Now I need to buy a new video card. I thought a card based on Nvidia 7900GT GPU.

My question is: a video card based on PCI-E 16x can work at lower speed (PCI-E 4x) ? Yes I know that PCI-E 4x is slower than PCI-E 16x, but PCI-E 4x is equal to AGP-8x and for now I'm satisfied.... In the future, if I'll change CPU and mobo with a real PCI-E 16x I'll have a video card 'PCI-E 16x ready'.....

Thanks in advance...
April 16, 2006 7:56:52 AM

There have been tests showing that videocards will not show a performance difference between an 8x AGP bus and a PCIe 16x bus.

It's not the bottleneck. I doubt there's be any difference at all in performance between PCIe 16x and PCIe 4x, unless there was a glitch in the chipset somewhere.
April 16, 2006 8:06:50 AM

My doubt is NOT for perfomance, but if IT CAN WORK ad different speed.
A video card AGP-8X can work (usually) in mobo with slot at 8x and 4x and (perhaps) 1x.
It's the same for PCI-E ? A card with PCI-E 16x can work in a PCI-E 4x slot ?
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April 16, 2006 8:17:36 AM

Ah.

Not to worry then, the ASUS P4V800D-X is made to take both AGP & PCIe graphics cards.
April 16, 2006 8:24:06 AM

Quote:
It's not the bottleneck. I doubt there's be any difference at all in performance between PCIe 16x and PCIe 4x, unless there was a glitch in the chipset somewhere.


Hmm, I'm a little skeptical on this one. Why would they impliment a new technology like PCI-e and not use it's bandwidth. If PCI-e 4x is just as quick as PCI-e 16x and PCI-e 4x is just as quick as AGP 8x, then what's the point in PCI-e?
April 16, 2006 8:28:27 AM

It's a tradeoff with that board, something to do with the way they jury-rigged AGP to work in tandem with a PCIe slot.
April 16, 2006 8:29:01 AM

So what you were saying was just about that one board?
April 16, 2006 9:34:21 AM

I'm saying the P4V800D-X has a bit of a tradeoff, even though it can use both AGP and PCI express videocards the tradeoff is that the PCI express port isn't fully 16x.

But that should have little to no bearing on performance. you'll be fine with it.

Try googling P4V800D-X benchmarks and reviews for a full picture.
April 16, 2006 9:41:05 AM

I thought that Pci-e x4 and Pci-e x16 were a physically different size?
April 16, 2006 9:42:38 AM

Not on this board. The graphics card slot is the standard size, it just has less thoroughput.

If you don't believe me, I encourage you to Google reviews of the board. There is only one PCIe graphics card slot, and this board has it.

That's the whole selling point of this board...
April 16, 2006 9:47:42 AM

Ah I see. Thanks for the correction
!