BES – Battle Encoder Shirasé
for Win XP/7/10/etc.

Open-source software that controls per-process CPU usage.

Version 1.7.7 (stable) – December 3, 2017

BES is a small tool that throttles the CPU usage of the process you “target”: for instance, you can limit the CPU usage of a process which would use CPU 100%, down to 50% (or any percentage you’d like). With this, you can use other programs comfortably while doing something CPU-intensive in the background. For more than 10 years, BES has also helped various gamers as a handy “anti-freeze” agent, though that was not the original purpose of BES. One of the well-known examples quick-fixed by BES is Witcher 3 (2015).


Usually try thisVer. 1.7.7 (December 3, 2017) Stable — SSE2 required (CPU from year 2000 or newer)
MD5 of zip = 7A3C11B829B7FF2B057CA2EA7B2D6D70

If you’re worried about false positives in Virustotal/Jotti (see FAQ below), you can use this build (Ver. 1.6.2) from 2014 instead (Virustotal, Jotti).
MD5 of zip = 1B5AAC7F841F0B9ED514FA035775608A

How to use it

Basically, just unzip the zip wherever you like and run bes.exe with admin privileges (right click > “Run as Administrator”). You don’t need to install it. When you don’t need it anymore, just delete the whole folder that you unzipped, and everything will be okay.

For more info: Read index.html in the zip and/or do some web search to see what others are saying about BES. There are guides in many languages. BES itself supports a few languages, e.g. French (BES : un limiteur de charge CPU pour quand il fait trop chaud pour travailler ....), Japanese.

Can BES fix the RDR2 CPU 100% problem?

Some users say yes (e.g. [PcGamingWiki][reddit]), others say no. It seems that BES is often (but not always) helpful if your CPU is i5; according to [], BES may help i3 users too. Make sure you run BES as admin. Try somewhere between −2% and −10% (Note, if you want to make your CPU load e.g. 97%, set BES as −3%). If you’re on Win10, try DirectX 12 (DX12) instead of Vulkan. If you’re on Win7 and anything doesn’t work, I suggest you wait and see if R* is able enough to fix the problems soon; upgrading to Win10 may not be a very good idea, because then you will have bigger problems every day (#1 forced updates, #2 privacy issues) and you won’t be able to play the game anyway unless you’re very lucky.

BES is a generic CPU limiter, not specifically designed to address the RDR2 issues, so don’t get angry even if it doesn’t work for you.

If you’re out of options: you can try your luck one last time with settings.xml (especially if your CPU is i5).

NOTE: This page (the official site of BES) has existed for about 15 years, originally having a tutorial with a lot of images. However, due to the RDR2 mess in Novermber 2019, too many gamers are coming here now, trying to get BES, which could cause a server down and/or too much transfer. Because of this, I have made this page plain and text-only (for the time being) to save server load and bandwidth. Previous versions of this page are on

FAQ: General

Q: Is BES free?
A: Yes. Free as in free beer (no charges), free as in freedom (open-source, GPL), and free of annoyance (no ads/no malware/no nag screens/no DRM/no phoning-home). It’s just a simple, small tool written many years ago for myself.
Q: Why can’t I see my target processes in the list?
A: Typically because you don’t run BES as admin.
Q: Is it possible to play my video more smoothly (without stuttering) while I limit it with BES?
A: Maybe, maybe not. (1) Don’t limit too much (e.g. −90%), instead limit lightly (e.g. −5%). (2) If you have to limit more (e.g. −50%), then after you start limiting, click [Control] in the main window and use a small value in Target Sleep/Awake Cycle. Maybe try 40, or even 30 or 20.
Q: Who uses BES, and why?
A1: BES helps an encoder when their CPU may be overheating (it is a software CPU cooler). Sometimes you may want your fans to be less noisy, even if encoding takes longer (e.g. when you encode something while sleeping in the same room).
A2: BES is also used by some gamers as a quick-fix, e.g. when the CPU load is too high.
Q: Is BES a good solution?
A: Sometimes yes, but there are often better solutions than using this tool. As for CPU overheating, the obvious solutions would be: (1) get rid of dust in your computer (e.g. by using canned air); (2) get a better cooling system.

FAQ: Safety

Q: Is BES safe to use?
A1: I could say yes, but that would be meaningless because I could lie. When you download anything, YOU should scan it with your anti-virus software.
A2: Another thing you may have to worry about: In some situations, BES may be seen as a cheat tool (e.g. it can slow a game) and you may face the consequences if you use BES. Be prudent and draw your own conclusion.
Q: Why do a few (less-known) anti-virus engines sometimes see BES as suspicious (false-positive), while well-known engines are generally okay with BES?
A1: Possibly because they are financially desperate and unethically advertising themselves by claiming, “We’re different. We can detect a virus that no one else can. Buy our products now!”
A2: To be fair, BES does look suspicious because it messes with other processes — it slows down the other program you target, not letting it run normally, by force-suspending and resuming its threads periodically. This unusual behavior of BES may be seen as suspicious, if heuristic malware detection is over-sensitive. It’s impossible for most end-users to tell if a program is really danregous or not, when their anti-virus software detects anything in it, and you couldn’t be too cautious about viruses, etc. Thus, if your anti-virus software tells you anything is bad, play it safe and listen to it. If you are a programmer and the same thing happens to you, the story is different: check the source code in the subfolder src in the zip (messy but the logic is simple and clear), and you will know that your anti-virus software is wrong.

FAQ: Misc

Q: What does the name “Battle Encoder Shirasé” mean?
A: A parody of Battle Programmer Shirase (Wikipedia). A person who encodes movies is called “encoder.” For what it’s worth, Shirasé is pronounced like she-rah-say.
Q: Who created BES?
A: Me — someone from, who encodes things.
Q: Can I use BES as a command line tool?
A: Yes. See Help - Commandline help (or hit [F2]), or read this (or index.html in the zip). Using command line parameters, you can also start BES automatically when you start Windows, and let it target specific process(es) pre-emptively, without manually limiting them every time.