PCI-E x1 Bandwidth Question

asinglenoob

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Sep 12, 2012
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Hello,

I've got a quick question for the community here. I'm going to be adding two PCI-E 2.0 x1 cards to my system, one for SATA III and another for USB 3.0. I'm wondering if each PCI-E x1 slot will have the full bandwith available to it, or if it's split between all the PCI slots on the system?

For example if I'm running an SSD off one adapter card, and USB 3.0 hard drives off the other will I get full bandwidth or will each device added to the PCI-E bus cut down the bandwidth of the others?
 

aicom

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Mar 29, 2012
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This all depends on how your motherboard is wired. It should make these details clear in the documentation. One thing I would note is that a SATA III controller is definitely going to bottlenecked by PCI-E 2.0 x1 (which is why most of the integrated Marvell controllers have a bad rap for performance issues).
 

asinglenoob

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Sep 12, 2012
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Thanks for the response! I realized SATA III would be bottlenecked by the PCI-E, but still faster than SATA II on the motherboard (although about 100mb/s slower than regular SATA III, from my understanding at least). This might seem like a daft question (because it probably is) but what should I be looking for in the motherboard manual that describes how the PCI bus works on my system?
 

asinglenoob

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Sep 12, 2012
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Okay I looked up my North Bridge (it's the AMD 770 model). According to Wikipedia: "One physical PCIe 2.0 x16 slot, one PCIe 2.0 x4 slot and two PCIe 2.0 x1 slots, the chipset provides a total of 22 PCIe 2.0 lanes and 4 PCIe 1.1 for A-Link Express II solely in the Northbridge" My Motherboard has one PCIe 2.0 x16 slot, and two of the PCIe 2.0 x1 slots. So I guess I'm still a little unclear as to exactly what that means for bandwidth?