Question Intel vs AMD & PCIe Lanes ?

[prince_xaine]

Hello, first I would like to formally thank you for taking the time to read the question and respond if you have an answer.

I'm asking the community rather than digging around because its a little difficult to get past all of the marketing BS between AMD and Intel. to be honest, I don't care which one I pick. I've really only owned Intel CPUs, but I'm no stranger to AMD installation either.

My main question here, is what are the offerings today? I've been out of the game for 5 years, still running with a i9-9900K. I'd like to pick whoever is offering the most PCIe lanes. I have a couple NVMe drives, a sound card for my sound equipment and a 4090 (recent upgrade - would like to upgrade the rest when I have time and money).

I'm not really looking to spend over $1000 on a CPU, so no Xeon or Threadrippers if it can be helped, but I would like to be able to install all of my PCIe devices without losing performance due to PCIe lane limitations.

Thanks again!

 

[Lutfij]

I'd like to pick whoever is offering the most PCIe lanes. I have a couple NVMe drives, a sound card for my sound equipment and a 4090 (recent upgrade - would like to upgrade the rest when I have time and money).
+
I'm not really looking to spend over $1000 on a CPU, so no Xeon or Threadrippers if it can be helped, but I would like to be able to install all of my PCIe devices without losing performance due to PCIe lane limitations.
You might want to first state your current system specs like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model.

 

[hotaru.hino]

For what's available now and with the latest consumer facing releases, both companies' CPUs provide 20 lanes directly to the CPU. This is usually split up between 16 for PCIe slots meant for graphics cards and 4 lanes for an NVMe drive. Additional PCIe lanes are provided by the chipset. How many and of what type depends on the chipset itself and how the motherboard manufacturer configured it.

For a socket AM5 for AMD and LGA 1700 for Intel, the platform that can potentially provide the most PCIe lanes is an LGA 1700 Z790 board at 48 total lanes (20 from the CPU, 20 PCIe 4.0 and 8 PCIe 3.0 lanes from the chipset). Though on AMD's side the one that provides the most lanes is an X670/X670E board, but it can only provide up to 20 lanes (12 PCIe 4.0 + 8 PCIe 3.0).

Regarding this setup though:

I have a couple NVMe drives, a sound card for my sound equipment and a 4090 (recent upgrade - would like to upgrade the rest when I have time and money).

You don't need an HEDT setup for this. Presuming "a couple" means 2, you only need 25 lanes for this entire setup, which almost any midrange to high-end motherboard can handle.

 

[bit_user]

For what's available now and with the latest consumer facing releases, both companies' CPUs provide 20 lanes directly to the CPU.

No, I don't think so. This diagram clearly states AM5 has 28 PCIe 5.0 lanes. Although, I take it 4 of those are used for chipset connection, where the chipset is limited to PCIe 4.0. That still leaves 24x direct-connected PCIe 5.0 lanes.

​

By contrast, Intel's Z790 gives you only 16 PCIe 5.0 lanes and 4 direct-connected PCIe 4.0 lanes. Where they do better than AM5 is in providing an 8-lane PCIe 4.0 chipset link.

​

This diagram is a bit confusing, because the outlined box in the upper-left is meant as a summary but they connected it so it looks like it's in addition to the x16 PCIe 5.0 and x4 PCIe 4.0 connections on the right side.

The one thing I know for sure is that AM5 is your only option for a PCIe 5.0 M.2 link, without cutting your graphics card down to x8 mode (which would be PCIe 4.0 x8, since there no PCIe 5.0 graphics cards, currently). For further details, see this guide to AM5 chipsets:

Guide to AMD Ryzen 7000 Motherboard Chipsets

When selecting a motherboard for your new Ryzen 7000 CPU, you will encounter three main options: X670, B650, and A620. But what are the differences, and what's...

www.techspot.com

 

[kerberos_20]

z790 = 20CPU+28chipset(16x PCIe 5.0, 24x PCIe 4.0, 8x PCIe 3.0)
= 48 lanes max

z670e = 24CPU+20chipset1+20chipset2 (24x PCIe 5.0, 24x PCIe 4.0, 16x PCIe 3.0)
= 64 lanes max

those are max lanes CPU+ chipset supports, they are configurable by mainboard (preffiled with hardware), meaning different mainboard has different amount of available PCIe lanes, but more or less available lanes are on both system about same (as they fill it up with SATA, ethernet, wifi and such things)..rougly 44 lanes on both systems are available

 

[hotaru.hino]

No, I don't think so. This diagram clearly states AM5 has 28 PCIe 5.0 lanes. Although, I take it 4 of those are used for chipset connection, where the chipset is limited to PCIe 4.0. That still leaves 24x direct-connected PCIe 5.0 lanes.

I made the assumption Zen 4 processors still had 20 lanes available to the user. Also AMD always counts the 4 used in the chipset as part of how many PCIe lanes the CPU has, which annoys me. I don't count them because, well, you can't use them, but I guess they can get away with it because it's a technical thing.

zX670e = 24CPU+20chipset1+20chipset2 (24x PCIe 5.0, 24x PCIe 4.0, 16x PCIe 3.0)
= 64 lanes max

Also forgot that the E boards double up on the chipsets, but looking at various block diagrams of it, doubling up seems to be more for expanding I/O ports that use PCIe rather than having them in the slots.



At the end of the day, I don't think OP really needs something that HEDT platforms used to offer and current consumer platforms are enough. Currently having that many PCIe lanes these days is only really useful if you want something like a data center made out of NVMe drives.

 

[prince_xaine]

Okay, so it seems it would be more so the motherboard/chipset than the CPU itself. That's fine, I suppose I can just stick with intel at this point (I don't like PGA and I assume AMD is still using it).

I will do some hunting from here to see what I can find, I'll check back here when I've picked something and choose a best answer at that point. Thank you for the insight.

 

[Order 66]

Okay, so it seems it would be more so the motherboard/chipset than the CPU itself. That's fine, I suppose I can just stick with intel at this point (I don't like PGA and I assume AMD is still using it).

I will do some hunting from here to see what I can find, I'll check back here when I've picked something and choose a best answer at that point. Thank you for the insight.

No actually AM5 was the first AMD (AFAIK) consumer CPU platform to use LGA.

 

[bit_user]

No actually AM5 was the first AMD (AFAIK) consumer CPU platform to use LGA.

Correct. AM5 is LGA.