Frank Steinmetzger wrote: > Am Tue, Jun 04, 2024 at 05:49:31AM -0400 schrieb Rich Freeman: > >> On Tue, Jun 4, 2024 at 2:44 AM Dale <rdalek1...@gmail.com> wrote: >>> I did some more digging. It seems that all the LSI SAS cards I found >>> need a PCIe x8 slot. The only slot available is the one intended for >>> video. >> The board you linked has 2 4x slots that are physically 16x, so the >> card should work fine in those, just at 4x speed. > I can never remember the available throughput for each generation. So I > think about my own board: it as a 2.0×2 NVMe slot that gives me 1 GB/s > theoretical bandwidth. So if you have 3.0×4, that is twice the lanes and > twice the BW/lane, which yields 4 GB/s gross throughput. If you attach > spinning rust to that, you’d need around 15 to 20 HDDs to saturate that > link. So I wouldn’t worry too much about underperformance.
Now this is interesting. So a good PCIe V3 card with a X4 connection could handle *almost* two dozen hard drives and still be able to transfer about all the data the drives can receive or send. That helps me a lot. Two 12 port cards with say 8 drives connected would handle pretty much everything I can throw at it. The Fractal case can't hold enough drives to fill up all the cards and mobo ports, yet anyway. 24 ports on cards, 4 on mobo, 28 hard drives. If I use a m.2 to SATA thing, that's another 6 ports, if they not sharing with a PCIe slot that is. >>> I'd rather not >>> use it on the new build because I've thought about having another >>> monitor added for desktop use so I would need three ports at least. > DisplayPort supports daisy-chaining. So if you do get another monitor some > day, look for one that has this feature and you can drive two monitors with > one port on the PC. That's something I didn't know. I wondered why they had that when a HDMI port is about the same size and can handle about the same resolution. It has abilities HDMI doesn't. Neat. :-D Sadly, the CPU I got is for processing only, no video support it says. >>> The little SATA controllers I currently use tend to only need PCIe x1. >>> That is slower but at least it works. > PCIe 3.0×1 is still fast enough for four HDDs at full speed. You may get > saturation at the outermost tracks, but how often does that happen anyways? > I can think of two cases that produce enough I/O for that: > - copy stuff from one internal RAID to another > (you use LVM, does that support striping to distribute I/O?) > - a RAID scrub > > Everything else involves two disks at most—when you copy stuff from one to > another. Getting data into the system is limited by the network which is far > slower than PCIe. And a full SMART test does not use the data bus at all. > > > But what I also just remembered: only the ×16 GPU slot and the primary M.2 > slots (which are often one gen faster than the other M.2 slots) are > connected to the CPU via dedicated links. All other PCIe slots are behind > the chipset. And that in turn is connected to the CPU via a PCIe 4.0×4 link. > This is probably the technical reason why there are so few boards with slots > wider than ×4 – there is just no way to make use of them, because they all > most go through that ×4 bottleneck to the CPU. > > ┌───┐ 5.0×4 ┌───┐ 4.0×4 ┌─────────┐ ┌───┐ > │M.2┝=======┥CPU┝━━━━━━━┥ Chipset ┝━━━┥M.2│ > └───┘ └─┰─┘ └─┰─────┰─┘ └───┘ > 5.0×16┃ ┃ ┃ > ┌─┸─┐ ┌────┸─┐ ┌─┸────┐ > │GPU│ │PCIe 1│ │PCIe 2│ > └───┘ └──────┘ └──────┘ > > Here are block diagrams of AM5 B- and X-chipsets and a more verbose > explanation: > https://www.anandtech.com/show/17585/amd-zen-4-ryzen-9-7950x-and-ryzen-5-7600x-review-retaking-the-high-end/4 > > Theoretically, the PCIe controller in the CPU has the ability to split up > the ×16 GPU link into 2×8 and other subdivisions, but that would cripple the > GPU, which is the normal use case for such mobos, so the feature is very > seldomly found. > > If I look at all available AM5 mobos that have at least two ×8 slots, there > are just seven out of 126: https://skinflint.co.uk/?cat=mbam5&xf=19227_2 > You can also use the filter to look for boards with 3 ×4 slots. > Nice block diagram. You use software to make that? Anyway, I looked at the skinflint link, those boards are pricey but still don't feature lots of PCIe slots. I've came to the realization that a lot of mobos are geared more towards gamers whether it is in the name or not. Very few, maybe any, are basic mobos with the ability to expand with whatever tools a user needs, be it lots of USB ports, wi-fi, drive controllers or any other device needed. My current Gigabyte has the basic tools; ethernet, USB ports for keyboard and mouse plus a few extras for the front of the case. Then it has PCIe slots for whatever the user needs to add. They can even be custom controller cards for lights, freezers or whatever. Current mobos, don't have that ability. One would think that they would still make basic boards for those who don't game as a primary use if they game at all. I realize things are always changing but not everyone uses a computer to play games on. Heck, they actually make custom game boxes just for the person who does. Everything about those game boxes is tailored for gaming, and very well at that. They put all the horsepower they can towards gaming and very little else. I've never had one but know people, including family, that does. Even the slightly older game boxes still do very well. For gaming, they can be a better option. I'm more happy with the current path than the one I was on. I'm hoping to find a mobo later that is geared more to my usage and build it, once I get this one paid off. Maybe by then they will have more slots or something and make finding what I need easier and not so expensive. It may be that I end up getting a server board. It may not. I dunno yet because the future isn't very clear. I do intend to write ASUS and Gigabyte about this. Maybe they are ignorant to the fact that some people need the basic tools on the mobo and then use slots to expand with what we need. It won't hurt to explain that to them. It might fall on deaf ears, it might make them think of a way to make at least one mobo model that fits that use case, and even help their sales. I can't be the only one. All the parts are coming. I even ordered a heat sink for the m.2 thingy. I saw on several videos that they can get hot, especially the controller chip, and then limit speeds to not let the smoke out. Also realized I ordered the wrong size fans for the Fractal case. I ordered 120mm, it takes 140mm. I got a pack of those on the way. At least now I have plenty of extra 120mm fans. LOL Most stuff will be here Monday. I also decided to put the new build in the Fractal case. I realized I have several drives that I don't backup so I don't need as much room for drives in my second, current first, rig. The space I use for torrents does expand faster than my other data. I don't backup that data. It's currently three drives but next expansion, it will be four. The drives currently on that LVM is about as large as I can get. One day, I may put the torrent drives on one system and run the torrent software from there instead of my main rig. I got to figure out how that works first tho. How to add/remove torrents. Is it GUI based or command line. I'll get to that later tho. Waiting on Monday. My little m.2 stick is already late. Supposed to be here today, maybe tomorrow now. Or Monday. I'm still very grateful for all the help from everyone. Some are so full of info it is hard to grasp it all. Some emails I read three or four times to try to get it in my head. If only they made a affordable mobo with lots of PCIe slots, X8 would be nice. Dale :-) :-)
