We wouldn’t trust AI with actively changing our PC settings. But we often wonder what it recommends as starting points for gaming PC users investigating their own systems. Specifically, we wondered whether ChatGPT had any sensible notes to share about one area many PC owners stay out of: the BIOS, or UEFI in more modern systems.

The UEFI (Unified Extensible Firmware Interface) or BIOS (Basic Input/Output System) features the motherboard-level controls that impact how your system works. So changing things here has a significant impact on your PC performance, functionality, and day-to-day use. If you know what you’re doing, there’s a wealth of options here.

But where do you start? ChatGPT suggested the tweaks below, but we’d recommend a bit more research for a couple of these – and (always) expert guidance if you’re unsure. To access your UEFI or BIOS, check your motherboard manual. As your system turns on, pressing and holding the Delete, ESC, or a specific F-key often grants access. Our views are below each tweak.

1. Enable XMP (Intel) or EXPO (AMD)

Loads your RAM’s advertised speed and timings instead of the default JEDEC profile.

• Benefit: Often one of the biggest free performance gains, especially in CPU-limited games.

If you built your system yourself, this is one of the easiest tweaks to forget. Usually found in the ‘Advanced Settings’ and then under ‘Overclocking’ (wording depends on the motherboard menu), you’re looking for ‘enable XMP’ if you have an Intel CPU, or ‘enable EXPO’ if you have an AMD CPU. This sets a default enhanced profile for your RAM to optimize your PC speed.

2. Enable Resizable BAR (ReBAR) / Smart Access Memory (SAM)

Allows the CPU to access the GPU’s full VRAM instead of small chunks.

• Benefit: Can improve gaming performance in supported games, typically by a few percent but sometimes more.

Another easy toggle if your system supports it. And, if your system has components from around 2020/1 or later, it probably does. ReBAR (Nvidia/Intel GPUs) and SAM (AMD GPUs) require CPU, GPU, and motherboard compatibility to work. If you have the option, it’ll be under ‘Advanced’, and then in your PCIe settings. Turn it on, and it may boost your GPU performance into double digits percentage-wise. That’s good for gaming. There’s no benefit to keeping it off unless you experience issues with it.

3. Enable Precision Boost Overdrive (PBO) (AMD CPUs)

Lets compatible Ryzen CPUs boost more aggressively when thermal and power limits allow.

• Benefit: Improves performance in gaming and multi-threaded workloads without manual overclocking.

An AMD-specific tweak that once again will be found under ‘Advanced > Overclocking’ (or similar) in your UEFI settings. AMD’s PBO settings mean your CPU can automatically boost performance, which may mean faster gaming. However, using PBO does require careful research, as temps and power draw will increase, and testing is sensible to ensure your PC runs well. PBO also voids the warranty on AMD CPUs. So we’d advise skipping this unless you’ve nothing to lose.

4. Set the PCIe Link Speed Correctly

Ensure the primary PCIe x16 slot is configured for the highest supported generation (for example, Gen 4 or Gen 5, depending on your motherboard and GPU), or leave it on Auto if the system is stable.

• Benefit: Helps ensure the graphics card operates at its maximum supported bandwidth.

This is an odd one, and not something we’ve ever recommended. Something modern PCs are pretty good at is dynamically changing speed to save on power draw. There may be some niche cases where your PCIe Link Speed (impacting GPUs, SSDs, and other PCIe devices) is incorrect. But this is usually set to ‘Auto’, as is best.

If you’re not sure about PCIe speeds, PCIe 3.0 should offer 8GT/s, PCIe 4.0 should offer 16GT/s, and PCIe ver 5.0 should offer 32GT/s. A tool like HWiNFO can display your maximum “PCIe Link Speed” at the bottom of the ‘dGPU’ sensors (I have a PCIe 4.0 system, and mine says 16GT/s). So we’d probably leave this BIOS/UEFI setting alone unless you’re concerned there’s an issue with your SSDs or GPU while you’re gaming.

5. Enable Above 4G Decoding

Often required alongside Resizable BAR on modern systems.

• Benefit: Improves compatibility with modern GPUs and is necessary for ReBAR to function correctly on many platforms.

While ChatGPT’s description isn’t wrong, the benefit of ‘Above 4G Decoding’ being enabled is more wide-reaching. This setting allows GPUs to secure larger-than-4GB blocks of addressable memory (a limit going back to 32-bit computing). If your GPU has more than 4GB VRAM, this is a boost. And if you want to enable ReBAR or SAM for GPU gains, you’ll first need this toggled on.

Furthermore, if you use additional PCIe expansion cards (for example, capture cards, NVMe PCIe or RAID adapters), you should enable this. It can help your system use more devices without them fighting for resources – which may also prevent hardware conflicts. Find it in your UEFI/BIOS settings under the PCI sub-menu.

Final thoughts

So there you have it. ChatGPT advised some useful BIOS settings to change or monitor. But experience and nuance are needed to understand why and how these changes are important. If you have a prebuilt PC, check with your PC builder if you have concerns about these settings or other motherboard issues. If you’ve built your own PC, these could be worth checking, but always weigh up the benefits and considerations of each before changing settings.