PCIe Lanes Confusion

[FinnR730]

Linus' recent video linked below has left me a little confused so I hope someone can help me out

 

http://linustechtips.com/main/topic/228327-pcie-lanes-pcie-8x-vs-16x-in-sli/

 

I got an Intel i7 3770k running on an ASRock Z77 Extreme 4 board and currently I have a graphics card (Asus GTX 760) and a Wi-Fi card on my board. My CPU has 16 PCIe lanes so I'm assuming that my GPU is running 8x and the Wi-Fi card 1x (please correct me if I'm wrong) I want to run two graphics cards in the future and though it will not initially be an SLI setup I do want to be running both cards in 8x

 

To do this will I have to remove the Wi-Fi card? (use a USB Wi-Fi thing instead perhaps)

Will the two graphics cards automatically be running 8x 8x?

Also if I remove the Wi-Fi card before adding a second graphics card will the single card automatically run at 16x?

 

I have tried reasearching this myself but the information is rather unclear so if anyone can inform me it would be much appreciated and thanks in advance to anyone who replies

[DildorTheDecent]

-words-

I have a WiFi card installed in a 1x slot and both my GPUs installed in 16x slots (running 8x/8x) and haven't noticed any drops. Although my motherboard does feature a PLX 8747 chip which gives an extra 32 PCI-E lanes i believe. 

 

You might have to remove your WiFi card. Since Nvidia cards require that you run at a minimum of 8x/8x to use SLi.

[FinnR730]

I have a WiFi card installed in a 1x slot and both my GPUs installed in 16x slots (running 8x/8x) and haven't noticed any drops. Although my motherboard does feature a PLX 8747 chip which gives an extra 32 PCI-E lanes i believe. 

 

You might have to remove your WiFi card. Since Nvidia cards require that you run at a minimum of 8x/8x to use SLi.

I thought this would be the case, I wasnt shure though. Will my graphics card(s) automatically run at the highest number of PCIe lanes possible? (16x / 8x 8x)

[Toddwjp]

I thought this would be the case, I wasnt shure though. Will my graphics card(s) automatically run at the highest number of PCIe lanes possible? (16x / 8x 8x)

 

i think they will i used a wifi card in PCIe with 2 770s on a 16lane cpu, motehrboard was a z77 sabertooth

 

its was the pc with the most 7s ever

[DildorTheDecent]

I thought this would be the case, I wasnt shure though. Will my graphics card(s) automatically run at the highest number of PCIe lanes possible? (16x / 8x 8x)

Yes. If you had two cards with 32 lanes available, They'd run at 16x/16x. If you have 16 lanes, they'd run at 8x/8x. 

 

Three and four card configs work differently depending on manufacturer. 

[FinnR730]

i think they will i used a wifi card in PCIe with 2 770s on a 16lane cpu, motehrboard was a z77 sabertooth

Thanks for info looks like Wi-Fi cards don't affect PCIe lanes perhaps

Yes. If you had two cards with 32 lanes available, They'd run at 16x/16x. If you have 16 lanes, they'd run at 8x/8x.

Three and four card configs work differently depending on manufacturer.

Okay thanks for the info

[Faa]

Your board is probably a 8x/4x/4x config instead of a 8x/8x/4x config. With the first config you can't have 2Way SLI and a wi-fi pcie card installed because the 2nd gpu slot shares bandwidth with the 3rd pci-e slot. However if you decide to get rid of your wi-fi card, it will be 8x/8x and SLI will work fine.

[FinnR730]

Your board is probably a 8x/4x/4x config instead of a 8x/8x/4x config. With the first config you can't have 2Way SLI and a wi-fi pcie card installed because the 2nd gpu slot shares bandwidth with the 3rd pci-e slot. However if you decide to get rid of your wi-fi card, it will be 8x/8x and SLI will work fine.

Thankyou, looks like I will have to buy a USB Wi-Fi thing before I add a new graphics card

[TheProfosist]

There are also x8 of PCI-E 2.0 coming off of the chips, which is likely what your WiFi card is using. It's also what board manufacturers try to use first rather than gpu lanes. On Z97 and X99 it's gotten hard though because of SATAe and M.2.

[Faa]

There are also x8 of PCI-E 2.0 coming off of the chips, which is likely what your WiFi card is using. It's also what board manufacturers try to use first rather than gpu lanes. On Z97 and X99 it's gotten hard though because of SATAe and M.2.

You haven't bothered to read my comment, right? Cheap boards tend to not take advantage of the chipset. Hence why you see a z68-v pro gen3 having a config of 8x/8x/4x and a cheap MSI z77 board of 8x/4x/4x because it only takes lanes from the CPU.

[-rascal-]

Adding to @Faa 's comment, according to AsRock, your motherboard has two separate PCI-E 2.0 x1 slots provided.

These PCI-E 2.0 slots are from the chip set.

In other words, no need to worry if you plan to SLi.

- 2 x PCI Express 3.0 x16 slots (PCIE2/PCIE3: single at x16 (PCIE2) / x8 (PCIE3) or dual at x8/x8 mode)

- 2 x PCI Express 2.0 x1 slots

- 2 x PCI slots

- Supports AMD Quad CrossFireX™ and CrossFireX™

- Supports NVIDIA® Quad SLI™ and SLI™

[TheProfosist]

You haven't bothered to read my comment, right? Cheap boards tend to not take advantage of the chipset. Hence why you see a z68-v pro gen3 having a config of 8x/8x/4x and a cheap MSI z77 board of 8x/4x/4x because it only takes lanes from the CPU.

Actually x8/x8/x4 is 16 lanes from the CPU and 4 from the chipset. The other 4 were likely chewed up by stuff they MB manufacturer put on like usb 3.0 controllers.