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What determines the Version of PCI-Express your computer is running?

Last response: in Components
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March 3, 2011 10:52:55 PM

Hello,

I am so confused.

Is this Version of PCI-Express determined by your motherboard, CPU, chipset or BIOS or some other factor that I have not found information on? Or is it a combination of factors?

Initially, I was trying to determine the version that my computer is running, but, now I am more interested in the whole mechanics behind what determines this.

Thanks in advance for any help.

a c 236 V Motherboard
March 3, 2011 10:56:30 PM

Your motherboard manufacturer determines what PCI-Express Version is built into the motherboard.

Your chipset determines what speeds PCIe x16 runs at in single, dual, triple... etc. Also, how it is effected by the other devices installed (for example).
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a b V Motherboard
March 3, 2011 10:57:53 PM

Its determined entirely by the motherboard and how it chooses to split the lanes that are provided by the CPU or chipset. The chipset or the CPU provides the PCI-E lanes but a motherboard that is provided PCI-E 2.0 lanes can also have a PCI-E 1.0 slot because you need half as many 2.0 lanes to get the same bandwidth as a 2.0 slot so it can emulate it.

Easiest way to check what version you have is if you know your motherboard you can find it on newegg or google it and that will likely have it listed. Another option if you have a dedicated GPU is to use GPU-Z and see what it lists as the interface.

Edit: Must type faster to beat tecmo :p 
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March 4, 2011 1:41:25 AM

All excellent answers!

I have a new Dell Inspiron 850.
Processor i5-760,2.8, 8 MB, Lynnfield,95W,B1
Intel Chipset H57

The chipset is capable of the PCi-E 2.0, but as you have confirmed it is motherboard dependent.

Dell told me that the manufacturer of the MB is Foxconn - but, would not provide a model number. (I assume that they are custom made for Dell), so I can't get the specs on the MB. Tech support was less than helpful on the phone.

Is there a reason that a manufacturer would use one PCi-E version over another? If it is cost associated I am going to assume (perhaps wrongly so) that Dell went for the less expensive option.

I also ran CPU-Z which verified the PCi-E, but did not denote the version.

In any case, thanks for the help, you guys cleared up my general confusion.




Thank you very much for your time.
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a c 222 V Motherboard
March 4, 2011 4:48:55 AM

The motherboard is the Foxconn DH57M02 (Skywalker) made for Dell.

According to the Dell Inspiron 580: Comprehensive Specifications document
Expansion Slots
...
PCI Express x16
Connector one
Connector size 164-pin
Connector data width (maximum) 16 PCI Express lanes
Bus speed 16 GB/s (bi-directional) <=== This is PCI Express 2.0
...
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March 4, 2011 11:17:52 AM

Thank you all so much!

Further research based on ko888's answer yielded the following table, which should help others determine PCI-E version based on specified bus speeds:

PCI Express in all it's flavors: 1x, 2x, 4x, 8x, 16x and 32x all have much greater bandwidth than basic PCI.

Common Buses and their Max Bandwidth
PCI 132 MB/s
AGP 8X 2,100 MB/s
PCI Express 1x 250 [500]* MB/s
PCI Express 2x 500 [1000]* MB/s
PCI Express 4x 1000 [2000]* MB/s
PCI Express 8x 2000 [4000]* MB/s
PCI Express 16x 4000 [8000]* MB/s
PCI Express 32x 8000 [16000]* MB/s
USB 2.0 (Max Possible) 60 MB/s
IDE (ATA100) 100 MB/s
IDE (ATA133) 133 MB/s
SATA 150 MB/s
SATA II 300 MB/s
Gigabit Ethernet 125 MB/s
IEEE1394B [Firewire 800] ~100 MB/s*


* Note 1 - Since PCI Express is a serial based technology, data can be sent over the bus in two directions at once. Normal PCI is Parallel, and as such all data goes in one direction around the loop. Each 1x lane in PCI Express can transmit in both directions at once. In the table the first number is the bandwidth in one direction and the second number is the combined bandwidth in both directions. Also please note that in PCI Express bandwidth is not shared the same way as in PCI, so there is less congestion on the bus.

Update: Table above contains speeds for PCI Express 1.0 bus. For version 2.0, multiply all bandwidths by 2. For example a PCI Express 2.0 16x slot has a max bandwidth of 8000 MB/s one way or 16000 MB/s both ways.

You guys are great!
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June 1, 2011 10:06:23 AM

Hi Hunter /Tecmo
So is a AGP 8x card still fractionally better than a PCI-e x4 card, or is PCI-e still better as it has 2 way traffic and it's dedicated bus lanes so to speak?
cheers
riggie

merlin123 said:
Thank you all so much!

Further research based on ko888's answer yielded the following table, which should help others determine PCI-E version based on specified bus speeds:

PCI Express in all it's flavors: 1x, 2x, 4x, 8x, 16x and 32x all have much greater bandwidth than basic PCI.

Common Buses and their Max Bandwidth
PCI 132 MB/s
AGP 8X 2,100 MB/s
PCI Express 1x 250 [500]* MB/s
PCI Express 2x 500 [1000]* MB/s
PCI Express 4x 1000 [2000]* MB/s
PCI Express 8x 2000 [4000]* MB/s
PCI Express 16x 4000 [8000]* MB/s
PCI Express 32x 8000 [16000]* MB/s
USB 2.0 (Max Possible) 60 MB/s
IDE (ATA100) 100 MB/s
IDE (ATA133) 133 MB/s
SATA 150 MB/s
SATA II 300 MB/s
Gigabit Ethernet 125 MB/s
IEEE1394B [Firewire 800] ~100 MB/s*


* Note 1 - Since PCI Express is a serial based technology, data can be sent over the bus in two directions at once. Normal PCI is Parallel, and as such all data goes in one direction around the loop. Each 1x lane in PCI Express can transmit in both directions at once. In the table the first number is the bandwidth in one direction and the second number is the combined bandwidth in both directions. Also please note that in PCI Express bandwidth is not shared the same way as in PCI, so there is less congestion on the bus.

Update: Table above contains speeds for PCI Express 1.0 bus. For version 2.0, multiply all bandwidths by 2. For example a PCI Express 2.0 16x slot has a max bandwidth of 8000 MB/s one way or 16000 MB/s both ways.

You guys are great!

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June 3, 2011 2:50:02 PM

Hi
Can anyone answer my question above please ?
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!