{
  "id": 19514338,
  "title": "Installing an SSD in the wrong M.2 slot can cut your GPU's PCIe bandwidth in half",
  "url": "https://urgent.news/2026/11/11/installing-an-ssd-in-the-wrong-m-2-slot-can-cut-your-gpus-pcie",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-11-11T15:00:21.000Z",
  "source": {
    "name": "XDA Developers",
    "slug": "xda-developers",
    "url": "https://www.xda-developers.com/installing-ssd-in-the-wrong-m2-slot-can-cut-gpu-pcie-bandwidth-in-half/"
  },
  "original_language": "en",
  "account": "When installing an NVMe SSD, it is crucial to consider the M.2 slot you choose, as it can impact other components in your system, even if the SSD operates at its advertised speeds. During an upgrade to the 9800X3D processor, the author installed a 2TB Crucial T710 Gen5 SSD in the primary M.2 slot, but also reused a Corsair MP600 SSD from an AM4 build. While reviewing the motherboard's specification sheet for remaining M.2 slots that support PCIe 4.0, the footnote revealed that using the second slot would reduce the RTX 4090's PCIe bandwidth in half. This is due to the M.2 slots on the motherboard obtaining their PCIe lanes either from the CPU or through the chipset, with a limited number of PCIe lanes allocated between components. In the case of the MSI X870E Carbon Wi-Fi motherboard, the first M.2 slot receives four dedicated PCIe 5.0 lanes from the CPU, while the third and fourth slots have four PCIe 4.0 lanes connecting to the chipset. The second slot shares lanes with the primary and secondary PCIe expansion slots, causing a PCIe bifurcation that splits the 16 PCIe lanes available to the GPU into an x8/x4/x4 configuration. This leaves eight lanes for the RTX 4090, four lanes for the MP600 SSD, and the remaining four for the secondary PCIe expansion slot. Motherboard manufacturers often advertise PCIe 5.0 support without providing clarity on lane sharing, emphasizing the importance of carefully reviewing the spec sheet, particularly the footnotes, to determine which M.2 slots share lanes with other components. While installing an SSD in the primary M.2 slot typically doesn't affect GPU bandwidth, certain Intel Z790 boards, such as the ROG Maximus Z790 Formula and ASRock Z790 Taichi, share PCIe lanes with the GPU even on the first M.2 slot. Thus, it is essential to verify your motherboard's specifications or manual before purchasing an NVMe drive to avoid losing half of your GPU's PCIe bandwidth, which may seem significant but typically results in only a negligible performance difference. In some cases, a PCIe 5.0 GPU running at x8 still offers the same bandwidth as PCIe 4.0 x16. If you prioritize having a second Gen5 NVMe without sacrificing any PCIe lanes from your GPU, consider opting for a motherboard that allows for this flexibility.",
  "summary": "Check your motherboard's spec sheet again, this time carefully.",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}