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Regarding MoBo with 4x PCIe

Last response: in Motherboards
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July 14, 2006 5:28:34 PM

Hi, maybe someone can shed some light on this issue. I want to upgrade to PCIe graphics card, but I currently have a 478 P4 3,2 HT CPU, which I don´t want to upgrade yet.

The only MoBo available here is the P4V800D-X from Asus, which has an AGP and also a PCIe slot, but the specs show that such PCIe port doesn´t work at 16x transfer rate, but 4x instead.

My question is if I´ll be able to use a high end graphics card (nVIDIA 7600 or 7900) without losing much performance, as I don´t know if these GPUs fill the 16x PCIe bus bandwith.

Anyways, it seems to be the only option to replacing the whole system including MoBo, CPU and Graphics Card...

More about : mobo pcie

July 14, 2006 5:45:30 PM

You could use it, but it won't work to it capabilities. The rest of your system is going to be the limit your speed. You'd be better off getting a cheaper AGP card because you'll see the same performance.
July 14, 2006 6:13:51 PM

Quote:
You could use it, but it won't work to it capabilities. The rest of your system is going to be the limit your speed. You'd be better off getting a cheaper AGP card because you'll see the same performance.


According to this theory, Which would be the bottleneck ? If the CPU is working at 200 MHz bus and the memory throughput is DDR, therefore 400 MHz; I understand that PCIe doubles the current PCI transfer rate which is 66 MHz, so we have a theorethical throughput of 133 MHz on PCIe.

I just don´t see how the rest of the system could be limiting the performance of the PCIe bus and the PCIe video card.
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July 14, 2006 6:16:19 PM

Suggestion...... 7800GS And A New Heatsink To OC That CPU
July 14, 2006 6:37:01 PM

Quote:
Suggestion...... 7800GS And A New Heatsink To OC That CPU


That´s something I had thought of as well, bu t I´ll still be stuck with AGP, besides the 7800GS AGP doesn´t come cheap.

Now, another factor for switching MoBo is DDR slots as now I only have three and I was running 1,5 GB but not Dual Channel, so I removed 1 stick. Now I need a 4 DIMM slot MoBo plus another 512 MB stick to run 2 GB Dual Channel.

BTW, I have a Thermalright XP90 so I OC to 3,45 GHz. Any ideas how far I can go with this heatsink without losing stability ?
July 14, 2006 6:42:15 PM

As far as I can tell from the Asus website that board has a 16x PCI-E bus. They claim it has 4x the bandwidth of 8x AGP, but thats only if you combine the upstream and downstream bandwidth of PCI-E since in AGP they are shared. You can probably use any card you want to with that board.

Edit: Aww crap... nevermind. 16x slot, 4x bus. My guess is that it will still perform pretty well with all but the highest end cards. I remember reading an article when PCI-E first came out where people benchmarked 16x cards with the bus restricted to 8x, 4x, and 1x (I think). It may have even been here on Toms...

Edit2: Yup it was a Tom's article. At least for gaming 4x seems to be more than enough.

-mcg
July 14, 2006 7:10:54 PM

Quote:
As far as I can tell from the Asus website that board has a 16x PCI-E bus. They claim it has 4x the bandwidth of 8x AGP, but thats only if you combine the upstream and downstream bandwidth of PCI-E since in AGP they are shared. You can probably use any card you want to with that board.

Edit: Aww crap... nevermind. 16x slot, 4x bus. My guess is that it will still perform pretty well with all but the highest end cards. I remember reading an article when PCI-E first came out where people benchmarked 16x cards with the bus restricted to 8x, 4x, and 1x (I think). It may have even been here on Toms...

Edit2: Yup it was a Tom's article. At least for gaming 4x seems to be more than enough.

-mcg


Thans for that link ! It really cleared out a few things regarding the PCIe transfer bandwith. I think I´ll give that MoBo a try, so I can stick to my 478 P4 and my GF6600GT while I choose a better card.
Thanks again !
!