Improving L3 Cache Throughput in Ryzen 5000 Processors

Introduction

If you have an AMD Ryzen 5000 Series processor, you should investigate whether or not you are running the latest BIOS version that is available for your motherboard. Updating your BIOS is one method for easily improving L3 Cache throughput in Ryzen 5000 processors.

BTW, updating the BIOS is also known as “flashing” the BIOS, which is that scary thing that many people don’t like to do. The standard disclaimer and advice from motherboard vendors is that if your system is working normally, then you should not update the BIOS.

There is a small risk that you can “brick” your system with a failed BIOS update. This doesn’t happen very often anymore, but it is a possibility. You also may have some disruption, because flashing the BIOS will reset most the BIOS settings to their defaults. This might cause some temporary issues that you should be able to correct by changing the BIOS setting back to where you had them before.

If you are still with me, lets talk about this in some more detail…

Background

AMD has recently released a couple of new AGESA versions for AMD AM4 B550 and X570 motherboards that are used by Ryzen 3000 Series and Ryzen 5000 Series CPUs. New AGESA versions are pretty common when a new CPU family or motherboard chipset are released. They fix a lot of bugs, make your system more stable and reliable, and sometimes improve performance.

AGESA version 1.2.0.1 is available for many MSI motherboards, including the MSI MAG B550 Tomahawk. In cryptic MSI-speak, BIOS Version 7C91vA61 is version A.61, as shown below.

Improving L3 Cache Throughput in Ryzen 5000 Processors
BIOS Version 7C91vA61

The rather sparse MSI release notes mention “Improving Ryzen CPU performance”. What might that be?

How Do I Know If My BIOS is Current?

First, you need to identify your motherboard and get the current BIOS version and date. The free CPU-Z Utility lets you do that. The Mainboard tab shows the motherboard make and model in the Motherboard section. It also shows the BIOS version and date in the BIOS section.

In this shot, I have BIOS version A.61 that was built on Feb 26, 2021.

Improving L3 Cache Throughput in Ryzen 5000 Processors
CPU-Z Mainboard Tab

Next, you need to find the support page for your motherboard on the vendor’s website. Every vendor is different, but most will have a BIOS section under downloads. Once you find that, you can compare the version and date you see in CPU-Z to what you see on the vendor support site.

The BIOS date you see in CPU-Z is the actual date the BIOS code was built, while the release date on the website is when that version was released.

If you are not on the latest version, you should consider updating your system so that you are.

Updating the BIOS on an MSI MAG B550 Tomahawk with M-Flash

I have a detailed blog post and a YouTube video that discusses and demonstrates how to update the BIOS on this motherboard. Other motherboard makers have similar procedures.

YouTube Video

AIDA64 Results Before BIOS Update

Here are the AIDA64 Cache and Memory Benchmark results for an AMD Ryzen 5 5600X processor in an MSI MAG B550 Tomahawk motherboard. This with BIOS version A.50, which has the older AGESA 1.2.0.0.

You want to look at the L3 cache results, which are the fourth row of boxes.

Improving L3 Cache Throughput in Ryzen 5000 Processors
Benchmark Results Before BIOS Update

AIDA64 Results After BIOS Update

Here are the AIDA64 Cache and Memory Benchmark results for an AMD Ryzen 5 5600X processor in an MSI MAG B550 Tomahawk motherboard. This with BIOS version A.61, which has the newer AGESA 1.2.0.1. This is in the same system, so the only difference is the BIOS version.

This looks like a nice improvement in L3 cache throughput!

Improving L3 Cache Throughput in Ryzen 5000 Processors
Benchmark Results After BIOS Update

Comparative L3 Cache Throughput Results

Here is the improvement in L3 Cache throughput on this system simply from doing a BIOS update.

AGESA VersionReadWriteCopy
AGESA 1.2.0.0281.09 GB/s279.39 GB/s294.67 GB/s
AGESA 1.2.0.1462.38 GB/s466.00 GB/s443.02 GB/s
Improvement62.7%66.8%50.3%
L3 Cache Throughput Improvement

Final Words

After updating your BIOS, make sure you don’t forget to re-enable XMP, so that your RAM is running at XMP speed instead of the much slower JEDEC speed. Running with XMP makes a big difference with some workloads.

Note that this L3 cache throughput improvement is does not mean that your system will be 50-60% faster! Whether you see or notice any improvement at all depends on what your workload is doing. Some software may see a nice increase from this and some may see virtually nothing. If your workload is bottlenecked on something else, improving this is probably not going to have much effect.

If you have any questions about this post, please ask me here in the comments or on Twitter. I am pretty active on Twitter as GlennAlanBerryThanks for reading!

AMD, PC Hardware

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