Most BIOS guides read like a server admin manual. They’re chock-full of settings, abbreviations, and often lack context for what it means for you day-to-day.
The good is that for most folks, there aren’t actually a great deal of BIOS settings that make a huge difference to performance. Whether you’re gaming, working, or otherwise, most BIOS settings don’t require any tweaks or tinkering. Not least because some BIOS settings can actually create issues.
However, nestled among the dizzying array of BIOS settings are four that are absolutely worth changing, and actually give you a performance boost.
Your RAM is probably running slower than you paid for
Change the XMP/EXPO settings
One of the most common performance-limiting BIOS settings relates to your system memory.
When you install RAM (even a kit rated at 6000MHz with “high performance” on the box), your system doesn’t automatically run it at that speed. By default, most boards fall back to JEDEC baseline speeds: whatever the DDR standard floor is for your platform. On DDR5 systems, that can mean running at 4800MHz when your kit is capable of 6000MHz or higher.
That’s because your RAM can be tweaked with different memory profiles, known as XMP (Extreme Memory Profile) on Intel platforms, and EXPO (Extended Profiles for Overclocking) on AMD platforms.
Memory profiles are fairly simple to find on most modern motherboards, but have different names on different motherboards, such as Ai Tweaker, OC Tweaker, Extreme Tweak, OC, and similar.
Your RAM is slower than you think — unless you enable this setting
Your RAM may be running slower than its capacity—here’s the simple BIOS setting that unlocks its full speed.
Before you start tweaking, double-check that your RAM and motherboard are fully compatible with higher memory profiles. A quick internet search for “[motherboard type] [ram type] xmp/expo compatibility” should reveal the information you need. Most motherboards have what’s known as a Qualified Vendor List (QVL), which specifically details the memory it supports.
Finally, if your system fails to post when you reboot after enabling XMP/EXPO, don’t panic. That typically signals you’ve used an incompatible memory profile. You need to head back to the BIOS and choose a different profile instead. Your motherboard may even have an automated option to use instead.
- Brand
-
Crucial
- Size
-
32GB (2x16GB)
- Technology
-
DDR5
- Speed
-
6400MHz
- Latency
-
CL32
The Crucial Pro DDR5 RAM 32GB Kit (2x16GB) delivers high-performance 6400MHz speeds with tight CL32 latency for enhanced responsiveness. Designed for gamers and creators, it features a low-profile aluminum heat spreader and universal support for Intel XMP 3.0 and AMD EXPO for stable, easy overclocking.
CPU power may be the answer if your PC feels sluggish
It’s being held back
I’ll caveat this one with the fact doesn’t affect every system, so don’t go looking for a problem that might not exist. You know what you’ll find then? Other problems. Still, if your PC feels sluggish and you can’t really put your finger on why, it could be that your motherboard has a defined power limit.
Basically, CPUs have defined power limits that govern how hard they can run over sustained periods. On AMD systems, this is expressed as PPT (package power), TDC (thermal design current), and EDC (electrical design current). Now, most motherboard manufacturers ship with these set to AMD’s default recommendations.
But some ship with them uncapped, and others may ship with them artificially restricted, which can mean your CPU is artificially restricted, and this is an issue that affects AMD hardware more than Intel.
On AMD hardware, you’re typically looking for Advanced CPU Configuration settings, where you’ll want to enable Precision Boost Overdrive (PBO), set to Auto. PBO essentially hands control of CPU boost back to AMD’s algorithm, which, for most folks, is perfect and shouldn’t cause any hardware issues.
What about Intel hardware?
Intel CPUs use a similar power limit framework — PL1 for sustained load, PL2 for short burst performance — and motherboard vendors can technically misconfigure these the same way.
However, it doesn’t tend to manifest in the same way as AMD hardware, as most Intel manufacturers ship with values as close to Intel’s rated specs as possible.
Make sure your NVMe mode is set correctly
Don’t forget about port-sharing
Now, there are two BIOS settings related to storage that can trip people up, both concerning the support and management of NVMe drives.
The first is the PCIe generation. Most motherboards are set to the correct NVMe generation out of the box, but, like the CPU issues, if your drive feels sluggish and you can’t figure out why, this could be the reason.
On some boards, the slot defaults to PCIe Gen 3 for compatibility reasons, or the setting gets changed during a BIOS update. A PCIe Gen 4 drive running at Gen 3 speeds is a hidden bottleneck. What I mean is that the drive still works, Windows doesn’t complain, but you’re getting roughly half the sequential throughput you paid for.
Most motherboards, AMD or Intel, have a specific section where you can adjust PCIe generations and storage options. You’re typically looking for an option named very similar: Storage Configuration, Storage Options, Advanced Storage, etc. From there, you’ll need to adjust the PCIe generation of the specific drive, which most motherboards label as M2_1, M2_2, etc., changing the setting specifically to PCIe 4.0, or to Auto if you prefer.
- Brand
-
Samsung
- Storage capacity
-
2TB
- Transfer rate
-
Read: 7,450 MB/s, Write: 6,900 MB/s
- DRAM
-
2GB
Watch out for bandwidth sharing
Second, and more importantly, bandwidth sharing. This is the issue that most people uncover when they add a second NVMe drive or mix NVMe and SATA storage.
On many boards, certain M.2 slots share bandwidth with SATA ports. Slide your new storage into the wrong M.2 slot, and you’ll disable one or more SATA ports entirely. Then, if you fill both M.2 slots simultaneously, you may find one running at reduced lane allocation.
While this feels like quite a few flaws in how your motherboard was manufactured, it’s more to do with the physical limitations of PCIe lane distribution.
It really means that before adding any extra storage to your motherboard, you should check the manual. There should be a bandwidth sharing table that shows which slots conflict with each other, and that’ll help you figure out the best options.
Resizable BAR one of the biggest performance boosts
It’s sitting on the table… if you have the right hardware
By default, the CPU can only access GPU VRAM in 256MB chunks at a time — a legacy limitation that made sense decades ago and makes no sense now.
Resizable BAR (on Nvidia hardware) and Smart Access Memory (on AMD hardware) remove that restriction and allow full VRAM access, delivering a substantial performance boost in the process.
ReBAR and SAM deliver the most performance in supported games, where some estimates and tests have seen up to 15 percent increases or more.
But while it feels like a BIOS performance boost tweak with little to no trade-off, it’s not as simple as hitting the switch and everything working perfectly.
|
Motherboard Brand |
Setting Name |
Where to find |
|---|---|---|
|
MSI |
Re-Size Bar Support |
Settings -> Advanced -> PCIe Subsystem Settings |
|
ASUS |
Resizable BAR |
Advanced -> PCI Subsystem |
|
Gigabyte |
Re-Size BAR Support |
Settings -> IO Ports |
|
ASRock |
C.A.M. (Clever Access Memory) |
Advanced -> Chipset Configuration |
|
EVGA |
Resizable BAR |
Advanced -> PCI |
Your hardware needs to hit a few conditions before ReBAR or SAM will work. For example, you need a UEFI BIOS configuration without any legacy/CMS settings enabled. You also need Above 4G Decoding enabled (to allow the firmware to map memory regions on PCIe devices above 4GB), along with a GPU that actually supports ReBAR and SAM, which covers most Nvidia RTX 30-series and above, and AMD RDNA 2 and above.
Snag the performance already available in your BIOS
There are more performance-based settings in your BIOS, but these four represent some of the most accessible performance-boosting options.
What makes them so useful is that, unlike most other BIOS options, they don’t require overclocking experience, exotic hardware knowledge, or any over-the-top risk to your hardware. In most cases, you flick the switch and watch the frames per second tick up. And what’s not to love about that?
