Posted October 27, 2015 Ok this is a question in relation to the pcie slots on a mobo (cpu controlled). I understand on most boards you get 20 lanes. So when you stick 1 video card in it runs at full x16. I also understand that M.2 drives basically use a pci e lane to achieve its break neck speeds. But if that is the case is the video card still running at x16? Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 Ok this is a question in relation to the pcie slots on a mobo (cpu controlled). I understand on most boards you get 20 lanes. So when you stick 1 video card in it runs at full x16. I also understand that M.2 drives basically use a pci e lane to achieve its break neck speeds. But if that is the case is the video card still running at x16? yes in skylake. No in haswell or before since they had 16 Judge a product on its own merits AND the company that made it. How to setup MSI Afterburner OSD | How to make your AMD Radeon GPU more efficient with Radeon Chill | (Probably) Why LMG Merch shipping to the EU is expensive Oneplus 6 (Early 2023 to present) | HP Envy 15" x360 R7 5700U (Mid 2021 to present) | Steam Deck (Late 2022 to present) Mid 2023 AlTech Desktop Refresh - AMD R7 5800X (Mid 2023), XFX Radeon RX 6700XT MBA (Mid 2021), MSI X370 Gaming Pro Carbon (Early 2018), 32GB DDR4-3200 (16GB x2) (Mid 2022 Noctua NH-D15 (Early 2021), Corsair MP510 1.92TB NVMe SSD (Mid 2020), beQuiet Pure Wings 2 140mm x2 & 120mm x1 (Mid 2023), Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 for Z170 you have x16 from the CPU + x4 from the PCH even when you have a SSD installed that uses PCI-E lanes you are only using the chipset lanes it wont affect the GPU lanes Budget? Uses? Currency? Location? Operating System? Peripherals? Monitor? Use PCPartPicker wherever possible. Quote whom you're replying to, and set option to follow your topics. Or Else we can't see your reply. Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 If your CPU supports 20 or more lanes, then your GPU will run in x16 and the m.2 drive will run in x4, making 20. If your CPU supports less than 20 lanes, the GPU will drop to x8 and the m.2 will still be at x4, making 12. Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 Skylake CPUs have 16 lanes just like previous generations. Graphics cards will be split x8/x8. SSDs and other peripheral devices will be connected to the auxiliary lanes which are 20 totally separate lanes that are provided by the Z170 chipset, in addition to the 16 lanes from the CPU. M.2 SSDs will not interfere with graphics cards at all, as they're run through completely separate PCIe controllers. Forum Rules | Guide to Display Cables / Adapters Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 I have a i7-5820k and a GTX 750ti and i noticed in my BIOS that the GPU is only running at 8xwhy isn't it at 16x? Desktop: CPU: I7-5820K GPU: 980Ti, 750Ti PhysX Mobo: MSI X99A SLI PLUS RAM: 4x4 Kingston DDR4 2400MHz OS: Win10Storage: 250GB Samsung Evo, 3TB WD Black and Green FIRESTRIKE, Reason for dedicated PhysX Card.Peripherals: Screen: 3x BenQ VZ2350 Mouse: Razer Naga Keyboard: Some Dell Thing Sound: Razer Tiamat, 5.1 Logitech Surround Speakers Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 I have a i7-5820k and a GTX 750ti and i noticed in my BIOS that the GPU is only running at 8x why isn't it at 16x? PCI Express devices are run at lower modes to save power when higher modes aren't necessary. Forum Rules | Guide to Display Cables / Adapters Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 PCI Express devices are run at lower modes to save power when higher modes aren't necessary. Ah ok so when i play a game or something it probably bumps up to 16. Desktop: CPU: I7-5820K GPU: 980Ti, 750Ti PhysX Mobo: MSI X99A SLI PLUS RAM: 4x4 Kingston DDR4 2400MHz OS: Win10Storage: 250GB Samsung Evo, 3TB WD Black and Green FIRESTRIKE, Reason for dedicated PhysX Card.Peripherals: Screen: 3x BenQ VZ2350 Mouse: Razer Naga Keyboard: Some Dell Thing Sound: Razer Tiamat, 5.1 Logitech Surround Speakers Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 Ah ok so when i play a game or something it probably bumps up to 16. Maybe, though games don't use a lot of PCI Express bandwidth either. Forum Rules | Guide to Display Cables / Adapters Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 Maybe, though games don't use a lot of PCI Express bandwidth either. In that case, is there any reason that video cards use PCI-E 16x slots? Is it just to make it reach the locking mechanism of the motherboard? Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 In that case, is there any reason that video cards use PCI-E 16x slots? Is it just to make it reach the locking mechanism of the motherboard? Graphics cards can use the full bandwidth. Games don't. If you run compute applications they'll take the whole thing. But mostly yes, it's just for standardization's sake that everyone uses the highest connector length. Forum Rules | Guide to Display Cables / Adapters Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 Graphics cards can use the full bandwidth. Games don't. If you run compute applications they'll take the whole thing. But mostly yes, it's just for standardization's sake that everyone uses the highest connector length. Ah thanks. Compute applications didn't occur to me. Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 Author Ok from what I have read so far, the following applies. NVMe drives or M.2 drives require a cpu controlled pcie slot to get the speed. If you use a chipset controlled pcie slot you will not get full speed. That being said : if a mobo has 20 lanes controlled by the cpu and you have 2 x pcie slots (cpu controlled) and your gpu uses 1 slot at 16 lanes, then the second slot can use x4 or "4 lanes" before it cuts the gpu back to x8 or "8 lanes" to accommodate for the extra lanes required on the second slot. Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
Posted October 27, 2015 cpu has 16 lanes chipset has 20 lanes (actually 26, but 6 are reserved so they can't be used, only Z170 and Q170 has the most PCIe lanes) Total combine useable lanes is 36. GPU uses lanes from your cpu, so 1 card installed will use up all the 16 lanes. 2 card installed then lanes are split into x8/x8 (Only Z170 chipset board with SLI support can do this) M.2 uses the lanes from your chipset. All of them supports PCIe Gen 3. On Z97 CPU has 16 lanes Gen 3 Chipset has 8 lanes Gen 2 On X99 CPU has either 28 or 40 lanes Gen 3 Chipset has 8 lanes Gen 2 Intel Xeon E5 1650 v3 @ 3.5GHz 6C:12T / CM212 Evo / Asus X99 Deluxe / 16GB (4x4GB) DDR4 3000 Trident-Z / Samsung 850 Pro 256GB / Intel 335 240GB / WD Red 2 & 3TB / Antec 850w / RTX 2070 / Win10 Pro x64 HP Envy X360 15: Intel Core i5 8250U @ 1.6GHz 4C:8T / 8GB DDR4 / Intel UHD620 + Nvidia GeForce MX150 4GB / Intel 120GB SSD / Win10 Pro x64 HP Envy x360 BP series Intel 8th gen AMD ThreadRipper 2! 5820K & 6800K 3-way SLI mobo support list Link to comment Share on other sites More sharing options... Link to post Share on other sites More sharing options...
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