Enable PCIe 5.0, DDR5 EXPO and Resizable BAR on a Ryzen Build

Most Ryzen builders leave real performance switched off in the BIOS simply because nobody told them which three toggles actually matter for a new build. Getting them right on a b650e motherboard takes a single BIOS session once you know where each one hides, not a rebuild, a fresh Windows install, or a trip back to the shop.

Quick Answer

Turning on PCIe 5.0, DDR5 EXPO and Resizable BAR is a short BIOS job rather than a hardware change. The ASUS B650E MAX Gaming WiFi, priced at R3,499, groups all three settings across a handful of AM5 BIOS pages, so a first-time builder can walk through every toggle in one sitting before the first boot into Windows.

⚙️ Getting PCIe 5.0 Running at Full Speed

PCIe 5.0 bandwidth covers the graphics slot on this board and stretches across its trio of Gen5 M.2 slots, but on some AM5 boards the slot still needs to be told, in BIOS, to run at its full rated generation instead of quietly falling back to a safer, slower link.

Where to Look for the Setting

Open the PCIe configuration page in BIOS and check the listing for the graphics slot plus each M.2 slot in turn, confirming each one reads Gen5 rather than an auto-negotiated lower speed. This matters most if you are carrying over an older GPU or SSD from a previous build, since some components report uncertain compatibility and the board negotiates down as a precaution.

A Detail Builders Often Miss

Reusing an older riser cable or a tired power supply cable can also trigger a lower negotiated link speed even when both the board and the card support Gen5, so check cabling before assuming a BIOS setting is wrong. Reseating the card fully in its slot and confirming the PCIe retention latch has clicked shut is worth doing at the same time, since a card sitting slightly proud of the slot can also negotiate down without throwing any error.

🚀 Switching Memory Over to EXPO

AMD EXPO does for Ryzen memory roughly what Intel's XMP does on the other platform, loading a manufacturer-tested profile rather than leaving a kit stuck at its slower baseline speed. It sits off by default even on kits sold to run near the 8000MT/s ceiling this board supports.

The Actual Steps

Enter BIOS, find the memory menu, often labelled Ai Tweaker or something similar, and pick the profile matching your kit's rated number. Save, reboot, and check the real running speed in Windows or a monitoring tool rather than trusting the number printed on the box.

What Happens If You Skip It

Leave that profile off and DDR5 settles at a conservative default speed well under what the kit can do, quietly capping performance in memory-sensitive games without throwing any warning or error message.

🎯 Turning On Resizable BAR

Resizable BAR lets the CPU read the graphics card's full memory pool in one go instead of smaller chunks, and it can measurably lift frame rates in supported titles. The toggle usually sits in the same advanced PCIe or CSM area as the PCIe generation setting covered above.

Confirming It Took

After saving the change, check your GPU vendor's control panel or a monitoring utility for confirmation that the feature shows as active, since some games and drivers need a restart, or even a driver reinstall, before they recognise it.

🧩 Running Through All Three in One Sitting

Because PCIe configuration, memory profiles and Resizable BAR all live on reachable AM5 BIOS pages here, a sensible order is the memory profile first, then a reboot to confirm speed, then a check of PCIe generation on the graphics and M.2 slots, finishing with Resizable BAR before one last reboot into Windows.

Saving the Result as a Profile

Once every setting checks out, save the full configuration as a BIOS profile. Doing this once means a future BIOS update or a CMOS reset does not force you to redo all three steps from memory, which is a small habit that pays off the day something eventually needs resetting.

For the full spec sheet, see this board's product listing. Builders weighing up alternatives across the same chipset family can browse Evetech's AMD B650 range, while the wider AMD motherboard catalogue covers other chipset generations for a broader comparison.

Frequently Asked Questions

Do all three settings need to be enabled together?

No, each can be switched on independently, though PCIe 5.0, EXPO and Resizable BAR each solve a different bottleneck, so doing all three gives the most complete result.

Does enabling EXPO risk the warranty?

Using a manufacturer-supplied memory profile counts as a standard, supported feature rather than a manual overclock, so it does not carry the same risk as hand-tuned voltage changes.

Can these be switched on after Windows is already installed?

Yes, all three live entirely in BIOS and can be changed at any point after the build without needing to reinstall Windows.

Does Resizable BAR work with every graphics card?

Support depends on both the GPU model and its driver version, so check compatibility for your specific card before assuming it will simply switch on.

What if my memory kit has no EXPO profile at all?

It will still run, just at its default JEDEC speed instead of any higher rated number, since there is no profile for the board to load.

Will any of this affect day to day stability?

Not if each setting matches your hardware's actual rated support; instability usually comes from pushing a kit or GPU beyond what it is rated for, not from using these features as intended.