Question Laptop PCI-E version question


Nov 2, 2015
Hello everybody, sorry this might be a dumb question but when doing some research it seems like my Ryzen 5900hx processor in my laptop only supports PCI-E 3.0 officially on AMD's website. However, when I go into CPU-Z and go to the mainboard tab it states that it is actually running a PCI-E 4.0 connection to the GPU with it stating 8.0 GT/s which is PCI-E 4.0 8x. Is this just a reporting error? I guess my question is does this laptop actually have a gen 4 connection between the CPU and GPU? If so is it only going to the graphics card? Is ASUS doing something special for the link to the CPU and GPU? For instance, if I wanted to upgrade to a gen 4 SSD in the future would I be able to take advantage of it, or would it be most likely if ASUS were doing something special to the 5900hx have a GPU 4.0 connection would it only exist for that and not NVME too. Thanks for your time. View:


The CPU and GPU support PCIe 4.0, yes. The chipset likely doesn't, so everything not connected directly to the CPU will be using PCIe 3.0.

For instance on B550, the CPU has PCIe 4.0 to both "graphics" slots, but all other slots are PCIe 3.0. X570 has PCIe 4.0 for everything.


Laptops don't run at the same speeds as desktops do. That's because mainly the CPUs and GPUs are designed to run on a batter, even a modern CPU like the 5900hx. So if you're thinking of adding something like a PCI Gen 4 M2 drive, keep in mind that the laptop will default it to PCI 3.0, so you're basically paying more money for less performance.
CPU-z may be making assumptions. Consider this:

GPU-z reported both RTX 30 GPUs that were paired with an AMD CPU as running on PCIe 3.0. And a cursory glance on GPU-z screencaps for the RTX 30 on a laptop also show PCIe 3.0. Plus I'd rather take what the actual manufacturer says over what a 3rd party app says.

This is only a "problem" if you were planning to stick a PCIe 4.0 SSD in there as mentioned. PCIe bandwidth is rarely a problem with GPUs and the only condition I'm aware of where it becomes a problem is if the GPU runs out of VRAM.


We have another thread going related to the 5600G, which is the same architecture, it also claims PCIe 3.0 only. But I can't confirm that with any diagrams or anything.

Only good diagram is of the silicon, and it just says PCIe...

Would love to know if the direct CPU connections are PCIe 4.0, and they claim PCIe 3.0 since that is what the platform supports?