Understanding PCIE lane questions Get clarity on your queries about PCIE lanes and their implications.
Understanding PCIE lane questions Get clarity on your queries about PCIE lanes and their implications.
I recently purchased a high-performance HP laptop featuring an RTX 3060 with 16 PCIe lanes, two Thunderbolt ports (each with four lanes), and two NVMe SSDs (one already installed, four lanes each). The i7-12700H processor supports up to 28 lanes. Based on your calculations, it’s currently utilizing all available lanes: 16 + (2×4) + 4 = 28. If you add another SSD to the second NVMe slot, using an additional four lanes, they will be sourced from the remaining capacity. Thanks for your assistance ahead of time. You can view the laptop here: https://www.hp.com/ca-en/shop/product.as...bl&sel=ntb
Typically, certain CPU PCIe connections route to the chipset, after which more channels are added, effectively splitting the available options
It's challenging to provide a definitive answer as locating the chipset diagram isn't straightforward. The impact on performance from adding an NVMe SSD usually depends on how the components are connected—whether they use CPU lanes or chipset lanes. It's likely the existing SSD and GPU are on CPU lanes, but without clear guidance on the chipset layout, it's hard to be certain. If you can open the laptop, examining the motherboard closely might help identify the connections.
It’s useful to identify which slots/ports come from the chipset since they distribute the available bandwidth among connected devices. Placing several high-end gadgets on these lanes can lead to problems such as lower frame rates or slower file transfers, depending on the specific devices and their usage.
CPU utilizes several PCI-E lanes, with some originating directly from the chipset. The lanes closest to the CPU tend to offer lower latency. On desktops, this usually means the top X16 slot and the top M.2 NVMe slot, though the exact positions can differ based on the CPU and chipset. The ARK page for the 12700H indicates 28 PCI-E lanes, indicating a CPU running on PCI-E 4.0 and a chipset version of 3.0. The M.2 SSD is connected via PCI-E 4.0 with four lanes. According to the spec sheet, secondary storage options match the NVMe specifications, suggesting your estimate of 16 lanes (for GPU) plus 4 from M.2 and another 4 from the chipset is reasonable. It seems safe to assume the dedicated GPU is on x16. I don’t have a complete chipset diagram, but I’m relying on the listed drive specs for both primary and secondary being 4.0, along with Intel’s ARK information about the chipset lanes. The remaining four lanes at 4.0 are likely allocated to the chipset as well.