{"video_id":"JGxWWvkOl98","title":"TWO Graphics Cards in ONE Slot?! - PCI Express Bifurcation","channel":"Techquickie","show":"Techquickie","published_at":"2021-05-05T14:58:16Z","duration_s":247,"segments":[{"start_s":0.24,"end_s":6.56,"text":"bifurcation it's a fancy word that means to split something into two and today","speaker":null,"is_sponsor":0},{"start_s":4.96,"end_s":10.48,"text":"we're going to talk about bifurcating something that isn't a sandwich a","speaker":null,"is_sponsor":0},{"start_s":8.4,"end_s":14.96,"text":"sporting event or a marriage this episode is all about pci express","speaker":null,"is_sponsor":0},{"start_s":12.8,"end_s":19.039,"text":"bifurcation this is exactly what it sounds like taking a pci express slot","speaker":null,"is_sponsor":0},{"start_s":17.199,"end_s":23.359,"text":"and chopping it up so that you can use multiple devices inside of it","speaker":null,"is_sponsor":0},{"start_s":21.119,"end_s":27.68,"text":"but how does that work i mean you can't exactly shove two graphics cards in one","speaker":null,"is_sponsor":0},{"start_s":25.6,"end_s":31.039,"text":"slot to answer we reached out to philip meyer from tian and we'd like to thank","speaker":null,"is_sponsor":0},{"start_s":29.359,"end_s":36.079,"text":"him for his contributions so the thing to keep in mind here is how pci express","speaker":null,"is_sponsor":0},{"start_s":33.44,"end_s":40.079,"text":"lanes are configured on modern platforms your CPU has a certain number of","speaker":null,"is_sponsor":0},{"start_s":38.239,"end_s":46.079,"text":"controllers and each one can only support one device for example even","speaker":null,"is_sponsor":0},{"start_s":43.36,"end_s":51.039,"text":"though a current Intel CPU supports 16 lanes it's split up with four","speaker":null,"is_sponsor":0},{"start_s":48.16,"end_s":55.28,"text":"controllers controlling four lanes each meaning you can connect a maximum of","speaker":null,"is_sponsor":0},{"start_s":52.879,"end_s":60.0,"text":"four pci express devices of course you can connect one graphics card and use","speaker":null,"is_sponsor":0},{"start_s":57.28,"end_s":64.479,"text":"all 16 lanes and just call it a day but let's say that you want to use multiple","speaker":null,"is_sponsor":0},{"start_s":61.76,"end_s":68.799,"text":"pci express storage devices like NVMe solid state drives this is where","speaker":null,"is_sponsor":0},{"start_s":66.4,"end_s":73.68,"text":"bifurcation comes in you see one of the most common uses of bifurcation is when","speaker":null,"is_sponsor":0},{"start_s":71.119,"end_s":78.0,"text":"you want to connect several m.2 drives to a single pci express slot this can be","speaker":null,"is_sponsor":0},{"start_s":76.32,"end_s":81.28,"text":"done using a fancy card that looks something like this but here's the","speaker":null,"is_sponsor":0},{"start_s":79.6,"end_s":85.92,"text":"kicker if you're going to chop up just one slot you need to tell your","speaker":null,"is_sponsor":0},{"start_s":83.04,"end_s":90.32,"text":"motherboard inside the BIOS exactly how to divvy up those lanes otherwise it's","speaker":null,"is_sponsor":0},{"start_s":88.4,"end_s":93.6,"text":"just gonna see one of those four devices and you're gonna regret spending the","speaker":null,"is_sponsor":0},{"start_s":91.52,"end_s":96.88,"text":"money how exactly you split up these lanes depends on what platform you're","speaker":null,"is_sponsor":0},{"start_s":95.119,"end_s":101.36,"text":"using as mentioned earlier the most you can do on a mainstream Intel platform is","speaker":null,"is_sponsor":0},{"start_s":98.799,"end_s":105.439,"text":"four devices with four lanes each but on a server platform like AMD epic you","speaker":null,"is_sponsor":0},{"start_s":103.439,"end_s":110.159,"text":"might get something like eight devices albeit with just two lanes each if you","speaker":null,"is_sponsor":0},{"start_s":107.92,"end_s":113.68,"text":"use that many bifurcation is a lot more common in enterprise settings as data","speaker":null,"is_sponsor":0},{"start_s":112.0,"end_s":118.159,"text":"centers tend to use pci express lanes for things that you just wouldn't find","speaker":null,"is_sponsor":0},{"start_s":115.28,"end_s":121.759,"text":"at home such as fpgas and asics chips and devices that can be highly","speaker":null,"is_sponsor":0},{"start_s":119.68,"end_s":125.52,"text":"customized to work on very specific kinds of operations but that doesn't","speaker":null,"is_sponsor":0},{"start_s":123.6,"end_s":130.239,"text":"mean that there aren't additional uses for pci express bifurcation at home like","speaker":null,"is_sponsor":0},{"start_s":128.08,"end_s":134.8,"text":"running two graphics cards in one slot although it's common for gamers to run","speaker":null,"is_sponsor":0},{"start_s":131.84,"end_s":138.56,"text":"just one graphics card at x16 speed running a card at x8 will make virtually","speaker":null,"is_sponsor":0},{"start_s":137.04,"end_s":142.879,"text":"no difference to your performance as even high-end modern cards don't move","speaker":null,"is_sponsor":0},{"start_s":140.8,"end_s":147.84,"text":"enough data to really need those extra lanes now obviously if you have a board","speaker":null,"is_sponsor":0},{"start_s":145.2,"end_s":152.08,"text":"with two free full-length pci express slots the lanes are automatically","speaker":null,"is_sponsor":0},{"start_s":149.2,"end_s":156.4,"text":"divvied up by a switch called a mux chip so that each card runs at x8 speed but","speaker":null,"is_sponsor":0},{"start_s":154.56,"end_s":162.239,"text":"there's actually nothing stopping you from sticking a two slot riser card into","speaker":null,"is_sponsor":0},{"start_s":159.04,"end_s":164.239,"text":"your pci express x16 slot plugging in","speaker":null,"is_sponsor":0},{"start_s":162.239,"end_s":168.56,"text":"two graphics cards with the help of riser cables and telling your BIOS to","speaker":null,"is_sponsor":0},{"start_s":166.319,"end_s":173.92,"text":"bifurcate the slot into two x8 connections just think you could run","speaker":null,"is_sponsor":0},{"start_s":170.56,"end_s":175.44,"text":"nvlink on a one slot mini itx board","speaker":null,"is_sponsor":0},{"start_s":173.92,"end_s":179.519,"text":"assuming you could find a way to mount the cards in your case so hopefully you","speaker":null,"is_sponsor":0},{"start_s":177.84,"end_s":183.36,"text":"don't mind using duct tape but if you're interested in using pci express","speaker":null,"is_sponsor":0},{"start_s":181.04,"end_s":187.519,"text":"bifurcation regardless of what exactly you'll be plugging in you need to verify","speaker":null,"is_sponsor":0},{"start_s":185.68,"end_s":191.519,"text":"that your motherboard and BIOS support it not all motherboards allow you to","speaker":null,"is_sponsor":0},{"start_s":189.599,"end_s":195.76,"text":"enable it in the BIOS and if that's the case it's pretty much a show stopper so","speaker":null,"is_sponsor":0},{"start_s":193.68,"end_s":200.4,"text":"do your research before you decide to turn your home rig into some sort of","speaker":null,"is_sponsor":0},{"start_s":197.599,"end_s":204.4,"text":"crazy science experiment big thanks to pia for sponsoring this video private","speaker":null,"is_sponsor":0},{"start_s":202.4,"end_s":209.68,"text":"internet access is the vpn that master ip and encrypts your internet traffic","speaker":null,"is_sponsor":1},{"start_s":206.8,"end_s":214.159,"text":"pia has reliable service with over 3 300 servers in 47 countries and no","speaker":null,"is_sponsor":1},{"start_s":212.319,"end_s":217.2,"text":"bandwidth caps it has configurable encryption and an internet kill switch","speaker":null,"is_sponsor":1},{"start_s":215.84,"end_s":221.04,"text":"to keep you in control of your connection and privacy and when you","speaker":null,"is_sponsor":1},{"start_s":219.2,"end_s":224.239,"text":"combine it with private browsing you can make websites think you're in a","speaker":null,"is_sponsor":1},{"start_s":222.48,"end_s":227.84,"text":"different country mister connect up to 10 devices at once with their clients","speaker":null,"is_sponsor":1},{"start_s":225.76,"end_s":232.159,"text":"for Windows mac Android iOS and Linux and stay protected with mace the","speaker":null,"is_sponsor":1},{"start_s":229.76,"end_s":237.92,"text":"built-in malware and tracking blocker to try it risk free for 30 days just head","speaker":null,"is_sponsor":1},{"start_s":234.159,"end_s":239.04,"text":"to LMG.gg slash pia techquickie so","speaker":null,"is_sponsor":1},{"start_s":237.92,"end_s":244.48,"text":"thanks for watching guys if you liked this video give us a thumbs up hit subscribe and be sure to give us a","speaker":null,"is_sponsor":1},{"start_s":242.159,"end_s":248.72,"text":"mention in the comments with your ideas for topics that we should cover in the","speaker":null,"is_sponsor":1},{"start_s":246.159,"end_s":248.72,"text":"future","speaker":null,"is_sponsor":1}],"full_text":"bifurcation it's a fancy word that means to split something into two and today we're going to talk about bifurcating something that isn't a sandwich a sporting event or a marriage this episode is all about pci express bifurcation this is exactly what it sounds like taking a pci express slot and chopping it up so that you can use multiple devices inside of it but how does that work i mean you can't exactly shove two graphics cards in one slot to answer we reached out to philip meyer from tian and we'd like to thank him for his contributions so the thing to keep in mind here is how pci express lanes are configured on modern platforms your CPU has a certain number of controllers and each one can only support one device for example even though a current Intel CPU supports 16 lanes it's split up with four controllers controlling four lanes each meaning you can connect a maximum of four pci express devices of course you can connect one graphics card and use all 16 lanes and just call it a day but let's say that you want to use multiple pci express storage devices like NVMe solid state drives this is where bifurcation comes in you see one of the most common uses of bifurcation is when you want to connect several m.2 drives to a single pci express slot this can be done using a fancy card that looks something like this but here's the kicker if you're going to chop up just one slot you need to tell your motherboard inside the BIOS exactly how to divvy up those lanes otherwise it's just gonna see one of those four devices and you're gonna regret spending the money how exactly you split up these lanes depends on what platform you're using as mentioned earlier the most you can do on a mainstream Intel platform is four devices with four lanes each but on a server platform like AMD epic you might get something like eight devices albeit with just two lanes each if you use that many bifurcation is a lot more common in enterprise settings as data centers tend to use pci express lanes for things that you just wouldn't find at home such as fpgas and asics chips and devices that can be highly customized to work on very specific kinds of operations but that doesn't mean that there aren't additional uses for pci express bifurcation at home like running two graphics cards in one slot although it's common for gamers to run just one graphics card at x16 speed running a card at x8 will make virtually no difference to your performance as even high-end modern cards don't move enough data to really need those extra lanes now obviously if you have a board with two free full-length pci express slots the lanes are automatically divvied up by a switch called a mux chip so that each card runs at x8 speed but there's actually nothing stopping you from sticking a two slot riser card into your pci express x16 slot plugging in two graphics cards with the help of riser cables and telling your BIOS to bifurcate the slot into two x8 connections just think you could run nvlink on a one slot mini itx board assuming you could find a way to mount the cards in your case so hopefully you don't mind using duct tape but if you're interested in using pci express bifurcation regardless of what exactly you'll be plugging in you need to verify that your motherboard and BIOS support it not all motherboards allow you to enable it in the BIOS and if that's the case it's pretty much a show stopper so do your research before you decide to turn your home rig into some sort of crazy science experiment big thanks to pia for sponsoring this video private internet access is the vpn that master ip and encrypts your internet traffic pia has reliable service with over 3 300 servers in 47 countries and no bandwidth caps it has configurable encryption and an internet kill switch to keep you in control of your connection and privacy and when you combine it with private browsing you can make websites think you're in a different country mister connect up to 10 devices at once with their clients for Windows mac Android iOS and Linux and stay protected with mace the built-in malware and tracking blocker to try it risk free for 30 days just head to LMG.gg slash pia techquickie so thanks for watching guys if you liked this video give us a thumbs up hit subscribe and be sure to give us a mention in the comments with your ideas for topics that we should cover in the future"}