EXPLAINED: PCIe lane SWITCHING & Biggest MISTAKES! | Don't DO IT 👉 WRONG slot for m.2 SSD!

okay there's a bit of a problem that I've seen in the comment section below people have heard that when you plug an end or two into the top slot of your motherboard like this one over there you're going to lose some of the other connectivity on the motherboard which is not right but it's also true but it's not right but basically there's something going on in there which is called PCA switching and it's sometimes happens and sometime doesn't happen but as a Creator it's very important to understand what is PC a switching when does it happen and when do you lose some of the bandwidth to some of the other components and when do you not so in this video I'm going to tackle that question and doesn't matter if you've never heard of PCI before you're probably going to understand what is going on so next time you upgrade some of the components in your PC you're going to know what's going on and if you're going to lose any features or not part of this video is sponsored by AMD thread Pro more about it later on in the video or in the description below so first we need to take a little step back back and talk about PCI Lanes now if you don't know what PCI lanes are and it what how do they work what are the different Generations Gen 4 Gen 5 like why does some CPU support Gen 5 some Gen 4 then I highly recommend my PCA Lane tutorial that I've made on the channel and I'm going to explain everything in detail in there whether you've heard about PCI Lanes before or not you're going to understand how do these work in your motherboard and why there are some things like that so I highly recommend going checking out that video first but then secondly what we need to talk about is the difference between PCA Lanes from the CPU and from the chipset so what I have over here is the um thread Ripper 5000 WX motherboard and this is the sage WiFi 2 this is the newer version of this but basically there's two places where the PCA Lanes can come from they can come from the chipset which is over here or the CPU now this is the same exactly so with some other motherboard boards for example this one here is the Phantom gaming motherboard from ack and here we have a chipset in here and then some of these PCA Lanes come from the chipset and then some of them come from the CPU so here's what's going on each CPU platform supports certain amount of PCA Lanes so when we looking at the thread rer 5000 here this supports a whopping 128 PCA 4.0 Lanes from the CPU all of those lanes are directly connected to the CPU which would be over there then if we looking at the likes of ryzen 7000 then these CPUs have 24 PCA Lanes on the CPU and these are PCA 5.0 Lanes now there's actually a little trick here this is actually 20 + 4 PCA Lanes so why is that plus4 there and what does that mean and AMD shows that actually on all of their specs that this is 20 + 4 so that plus four lanes is actually the four PCA lanes that connect the CPU to the chipset so there is actually a connection between the chipset and the CPU imagine like a some wires that go across so whatever is connected to the chipset essentially and eventually has to connect to the CPU otherwise you won't be able to access any of that information so whether it's SATA port some of the PCA slots some of the .2 slots if they're connected to the SE chipset because you've run out of PCI Lanes on the CPU for example then this is connected to the CPU and AMD uses something called PCI Lanes actually as well to connect to the CPU so there's 20 that come from the CPU and then four that's connected to the chipset and then chipset has extra Lanes but because you're not always using all of the connected things at the same time for example your ethernet or your PCA expansion lot slot there or mda2 a few m2s on the chipset we can get away with just a few PCA Lanes between the CPU and the chipset now with Intel it's very similar but slightly different at the same time so here we have the z790 chipset and there's some m2s here connected to the chipset and then Intel uses something called DMI connection with the CPU so there is still a connection between here the CPU and the chipset now between different generations of CPUs that might change how they're connecting the chipset to the CPU but there always will be some kind of connection there but what you need to understand and remember is that the connection between the chipset and the CPU is always not the full length of what connects to the chipset there's a smaller connection imagine this as like a lot of streams that flow into the chipset of data whether from mdda 2s or from some of the iio from the back or SATA port something goes to the chipset and then there's a little river that trickers back to the CPU so Intel actually has 16 +4 usable Lanes on the z790 R1 14th genen for example or any of the 12 13 14 Shen and that 16 + 4 isn't actually the same as amd's 20 + 4 because Intel has 16 PCA Gen 5 lanes and four PCA Gen 4 Lanes AMD has actually 20 PCI Gen 5 and then the plus 4 is for chipset if that makes sense but here's the problem I'll show you this here so I've got an Intel motherboard over here if I'm going to connect uh an Ender two on the top slot over here suddenly I'm going to lose half of the bandwidth of the first PCA slot which usually is used for C GPU so suddenly this is not 16 Lanes in there but eight Lanes in there but if we're looking at another motherboard over here this is the x670 pro art from Asus if I'm going to plug an M2 on the top slot there whether it's just Gen 5 or Gen 4 absolutely nothing's going to happen and I'm still going to have full 16 Lanes bandwidth for this first PCA slot in there and you might be saying wait a second why is this like that how can I find out if my motherboard has that or not I've seen a few comments in the comment section saying that oh I'm not sure if my proad z790 motherboard is going to lose the bandwidth if I'm going to put an m.2 uh SSD on the top slot and the answer is no but how do you find out that information before I show you how to find this information let's talk about the AMD ryzen thread Ripper Pro 5000 series which doesn't actually have any of the PCI Lane switching issues no need to worry about where you plug things in it's always going to run at full speed AMD ryzen thread Ripper Pro 5000 WX series offers up to 64 cores and 100 and 28 threads which offers unmatched multicore CPU performance for creators for programs like blenders Cinema 40 vray and many others the 5995 WX holds the clear lead in the market it features 128 PCI 4.0 lanes for the ultimate expandability whether you need to run eight gpus or expand your storage to Oblivion thread rippers got you covered no more PCI Lane switching go check out my world record Benchmark score in the Venture resolve achieved with the thread Ripper Pro 5995 WX couldn't do it without it check out thread Ripper Pro 5000 WX series CPUs in the description below and see how they can improve your workflow well that information you can find out in the motherboard manual now you might have a manual in the Box in paper form but there's always an updated manual on the all the homepage of your motherboard's websites whether it's proart or WRX Pro Series from Asus or gigabyte or azero or MSI whichever one there is a motherboard online as well where you can check not all motherboard manufacturers do this but some of them do but this is easier to understand what's going on uh in there if they don't have a block diagram which I'm going to explain in a minute what there is they will show you tips like when you pluging in something in the top slot some switching is going to keep going there it's called PCA switching and then how this is going to affect the performance in some of the other expansion slots either in the or some other places they will explain this they're there so highly recommend kind of browsing through the manual and then seeing like okay I'm going to install M2 slot so go to the end2 SE selection there or expansion slots on the motherboard and you'll understand something in there but uh here I want to use this Azo z790 Riptide Wi-Fi motherboard manual here as an example because they've done a very good job explaining this here so in this motherboard you've got this here which is the block diagram and and blog diagram basically explains and shows you how all of these different IO ports and expansion slots and all of the different headers and ports are connected to the CPU or to the motherboard and here we can see that this top bit here is the actual CPU so we can see what's connected to the CPU and some of the I/O you can see that there's the display port and HDMI from the back of the motherboard that comes straight to the CPU then we can see the m.2 D1 is is connected to the CPU so we've got PCI Gen 4 X4 Lanes so this is the plus 4 Lanes on the Intel here connected to the CPU then we've got some DDF 5 slots that are connected directly to the CPU which makes sense as well but here this bit is what's getting interesting here so basically because Intel CPU here the 14th gen or 13th or 12th gen only has 16 PCA Gen 5 Lanes but if you want to add another PCA Gen 5 storage option which which this top slot here actually provides then something's going to have to give somewhere because we only have 16 PC lanes and this explains exactly what happens so you can see that there is Gen 5 Lane here and you can see there little arrows here between these two things here okay so this is what's called PCI switching so if you have something connected only to this top slot here then you will have the full PCA gen 5x16 bandwidth of the GPU but there is a little switch in there as well that goes to the secondary slot in there so if you plug anything into the secondary slot then suddenly there's a switch that switches the first lane from 16 to 8 so you've got only eight in the top and then eight in the bottom that's PC Gen 5 Lanes now it gets a little bit more complicated I'll add a little section here that when you have your graphics card then the graphics card generation right now there isn't the graphics card out there that has PCA Gen 5 in interface on the actual graphics card so the graphics cards are most likely X8 or x16 x16 is the more popular x16 PCA Gen 4 Lanes so what will happen is if you put your PCA Gen 4 x16 card into this slot and you plug something else on the bottom slot as well perhaps another graphics card now they are not going to start to run at X8 Gen 5 speed because the graphics card doesn't support Gen 5 they'll start to run now at X8 so you've got eight Lane of PCI Gen 4 going to the graphics card in the top slot and on the bottom slot because it switches that which means that you might lose some of the bandwidth on your graphics card or whatever you know peripheral you have plugged in into there if it actually can utilize all of the 16 Lanes but now can only push all the data through the eight Lanes which just is you know smaller road to push all the data through which might cause some performance issues how much that's for another video but there is another switch here as you can see see there's like a two or three switches there's two arrows here the other switch is that if you have something plugged into the top slot here you will lose this main slot 16 slots again to X8 so whether you've got something plugged into there or to this top slot it doesn't matter if it's Gen 5 or not you will lose the bandwidth of this top slot there and that's what is called a PCI switching so knowing that that's very very important for example if you don't need a Gen 5 SSD then I highly recommend not using the top slot but using the secondary slot which still goes to the CPU here but you will get only Gen 4 Lanes but Gen 4 ssds is still very very good and you will get the full bandwidth to the CPU which basically is better because you don't have the latency issues if you plug it in something like on the uh third slot here there's an end of two slot in there what will happen is that data now travels to the chipset and then through the small Canal between the chipset to the CPU which just is a longer way around and latency issues and so on you want always the OS SS the m.2 SS what you have on your motherboard to connect to the CPU that will give you the best and quickest performance less lag and less going round and all the other data whether that's you know project drives or others they're kind of like secondary priority because if the OS is laggy everything else is laggy because that's where the programs and Os is running on but all the rest they can go to through the chipset and find their own time that's the best performance way basically there and then as you can see here we've got this big chipset and then they've got another chipset here on this motherboard where they've connected some other things into it they've added another little chipset but that connects to the chipset as well so basically there's another hobo thing that's going on and then you can see that this chipset here all these other things like all the uh headers 2.0 headers from the USB and front panel headers and all sorts of headers and things they connected through the chipset and then from the chipset boom to the CPU through these DMI gen 4x8 Lanes between there now in this motherboard we don't have actually any other switches as you can see so all the rest of the things that go through the chipset they go directly onto the chipset and you don't lose anything else in there but this is not all all because the AMD ryzen 7000 has actually more PCI Lanes well there's still 20 but the four that goes usually to the mda2 slot on Intel we have it at PCA Gen 4 but on AMD we have it at PCA Gen 5 which means that even if you plug something else into the top slot here this will still be PCA Gen 5 speeds or bandwidth which means you're not going to lose any bandwidth on the top slot here or anywhere else now there are still some switching going on when you get to the Other M the two slots ssds there but on AMD platform right now you can use a Gen 5 SSD and it will run at full speed and you're not going to lose anything else there but these are some of the you know mainstream or lowend desktops what I'd like to call them there is something else called a high-end desktop which is HT platform which what we have in here so this is basically workstation or high-end desktop there's not a clear borderline there which is which but basically what happens here is now the AMD thread Ripper CPU which I have here has 128 PCA Lanes going to the CPU which is as you can see quite a bit more than our Intel's mainstream platform and also quite a bit more than the ryzen 7000 CPU which takes this platform to a whole another level because you don't have you might have but most likely you don't have any problems with the PCI Lane switching and most of the things on the motherboard what you need the speed of are connected directly to the CPU for example if you plug something into the top slot boom x16 Lan to the CPU the same with the second bit over here third fourth slot you're thinking wait a second how many graphics cards can you run then at full speed well quite a lot depending on your motherboard I think this motherboard one of the slots runs at X8 speeds rather than all of them x16 but basically you can run about eight graphics card full 16 Gen 4 PCI Lane bandwidth to the CPU and you're not going to lose any of the bandwidth which makes this AMD thread Ripper completely in another leak Now intel has released the xen this is the fourth gen xen and this is is the 3475 x what I have here and this one does have 112 PCA Gen 5 Lanes so as you can see slightly less than the thread Ripper but these are PCI Gen 5 Lanes now if you do need the PCI Gen 5 storage you can definitely go for that one but the platform right now costs a little bit more than the thread Ripper and while this thread Ripper 5000 series is actually absolutely incredible incredible buy if you need some insane storage here's what I mean let's say you are a video editor renderer or whatever you're doing you need like two gpus okay whack two gpus in there one two you still have plenty of other expendability you can put a whole another 10 gbit card in there maybe this is a dual 4 10 gbit card you can put that one in there you're not going to lose any bandwidth capture card no problem add another bit of storage because this motherboard comes with the um Asus hyper m.2 expansion card for m2s so let's say you do need some more end twos what you can use is these this card here which is only one slot thick it has four m2os inside you plug them in there slot this card maybe into the bottom slot there boom add some more in there and you can create incredible amount of storage of Ender twos and you're not going to lose any of the bandwidth or you're not going to be like M okay some of the m2s are now running half the speed or the top member2 everything is running just the full speed and there's basically the end of PCA switching now this is thread Ripper 5000 which supports DDR 4 and right now is probably very very affordable because the new generation of 7,000 has just been launched now the 7,000 thread Ripper stay tuned for that video because um when we get those samples in this is a whole another level because now we have 128 PCA Gen 5 Lanes so basically we just doubled the bandwidth what this can do I mean there isn't yet a PC 5 peripherals out there imagine we have this card here but well I hope Asus is going to do that or some other people we're going to have this card as PCA gen five card you can put four PCA Gen 5 you know ssds in there slott it in there nothing's going to change and you can do that eight times so you can have eight of these cards with PT PCA 5 storage so that would be 8 * 4 that's 32 PCA Gen 5 slots on your motherboard and you're still not going to make any switches or something else you still have the full chipset that's connected to the CPU to get extra storage so you have 32 enter two slots let's say we can get this up to 8 terby at some point that that is incredible amount of storage with just connected to one CPU one CPU platform without losing anything so the conclusion of this video is think about what you need for your creative PC or perhaps some other productivity or high-end workstation PC if you're building this when you're upgrading this it's very good to know where your PCA lanes are and how this is routed how the PCA Lane switching is going on how the block diagram works so you know what to do so if you're on the Intel platform you have the least options there what you can do to expand and then not lose any you know connectivity but the question is do you actually need some of this bandwidth is completely another topic which we might explore in the future then we have the AMD system here for the Ryon 5000 which actually has a bit more PCA lanes and gives you more expansibility now you might pay a little bit of a higher price for the motherb but it's because you do get the more or higher M2 slot generation p N5 you're not going to lose it and you can just use both of them which is pretty interesting and obviously if you're running the thread Ripper platform this is where you are going to be opened up to A Whole New World of what you can do with your PC how you can expand this um what you can add to their storage in the end use it for a server however you want to do this it's absolutely incredible but the takeaways from this video would be understand the block diagram and if you want to populate the mda2 SSD especially esally for the operating system it's very very very very important that you don't plug it into the wrong slot this is one of the biggest mistakes that people do and you've seen me criticize J2 sense even to that um when they built their PC they lose some of the bandwidth but they didn't have to lose it but just by plugging something into the wrong slot they might lose some of the bandwidth to the CPU or to the you know graphics card and so on so make sure that your OS SSD that you installing is plugged into the correct slot it's not always the top slot that will make you lose the BCI you know Lane bandwidth over there it depends if the very top slot looks like some of the gigabyte B bods do that but not all of them when is Chen 5 on Intel platform you're most likely going to lose something right now in the Z 790 z690 platforms but with the AMD is the same if you don't have the higher end chipset like the x670 and you might still have the some Gen 5 mda2 advertised just double check that this is the right slot where you want to plug in your OS operating and program SSD because you might lose some of the bandwidth if you are not very careful and plugging this in but the good news is the create the motherboard like the z790 create the motherboard from Asus whichever one you populate they're all actually Gen 4 ssds which means you're not going to lose any bandwidth to the any of the other expansion slots you're completely fine hopefully this helped you understand the PCI switching why this happen how this works works and uh next time you're going to be a little bit smarter let me know what you think if anything was still a little bit unclear I'd love to know from you in the comment section below but if you are a Creator and you want to build the best bank forb Creator PC meaning the best performance for your money then check out the build guides in the description below they're completely free and there's one for your budget whichever one in is there's upgrades downgrades in there I'll explain everything down there go check them out thank you AMD for sponsoring parts of this video so if you do want to run more than one GPU in your setup and you're the ultimate creator for 3D or Architects or whatever and you don't want to worry about PCA Lane switching then check out the thread R Pro 5,000 Series in the description below it's an interesting platform because it's really got no competition at this point yet and now it's more affordable than ever so check it out in the description below because DDF 4 you know you can get up to 2 tab in there and uh you know it's more affordable than ever did I say that already yeah I did so go check it out thanks guys [Music] bye-bye

Channel: Tech Notice

Views: 129,491

Keywords: tech notice, best tech, pci express, pcie lanes, pci express lanes explained, pcie switch, pcie switch tutorial, pcie switch explained, pci express switch, why pcie switching happens, why do you loose PCIe lanes, PCIe lane swithing, explained, pcie slots, graphics card, pcie x16 vs x8, x16 slot, wrong slot for m.2, pci express explained

Id: I4umSUJyArs

Length: 24min 5sec (1445 seconds)

Published: Sat Nov 11 2023