PCIE 3.0 on Lenovo M73

The Lenovo M73 (10B7) is advertised to have a PCIE 3.0 x16 slot, but it has the Intel H81 chipset. Bios gives option to set slot to Gen 3 speed but my gpu is running in pcie 2.0. Is there a way to mod bios to fix this or does the chipset/motherboard limit it to PCIE 2.0? My CPU is an Intel Xeon 1231v3 if that helps. Thank you for any help or information!

The Intel H81 chipset supports pcie 2.0 x16.
They seem to copy paste the bios setting from an bigger chipset. What is your gpu?

ThinkCentre-E73-motherboard-won-t-use-PCIe-3-with-GPU-PCIe-speed-with-graphics-card - English Community - LENOVO COMMUNITY

Working as intended.

Intel limits the Processor PCIe Controller to 2.0 if using H81 Chipset. Read the Datasheet itself: https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/8-series-chipset-pch-datasheet.pdf#page=52
Processor PEG Port Maximum Speed Allowed: Gen 2 for H81, Gen 3 for everyone else. It is under the category of Processor Features Controlled by PCH SKU.

My GPU is the XFX AMD RX 6400, I know it’s designed for PCIe 4.0x4 but the performance hit on PCIe 3.0 isn’t much and I thought it would be a good fit for a small living room PC. And my own research was leading me to believe the Chipset was limiting it. Would there be no way for that to be bypassed, assuming Lenovo actually wired the slot for PCIe 3.0 specification?