# Corrupted OS from RAM Overclocking - how can I prevent this?



## aDyerSituation

I was messing with my ram timings on my patriot 2x8 4400cl19 kit
I had it at 4266 18-18-18-38 trfc 400, 1.25-1.3 for vccio and system agent. 1.4v for ram. and it was stable and decided to start tweaking it more.

I reset trfc back to auto and took the timings to 16-17-17-37 and raised voltage to 1.45 for the ram. After about 300% coverage in karhu I got an error. Restarted, raised the voltage, got an error about the same time. Then on the third reboot Windows would not reload and I could not repair it via command prompt or automatic repair. I could not system restore either, it would just blue screen if I tried to continue. I think the code was 0xc00021a.

So I reinstalled Windows no big deal, needed to do it anyway. I backup all my important stuff regularly, and I went back to the timings I had originally and tested overnight no errors. 

I've never actually corrupted my OS from tweaking ram, what did I do wrong and is there anything I can do to prevent this in the future?


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## Falkentyne

aDyerSituation said:


> I was messing with my ram timings on my patriot 2x8 4400cl19 kit
> I had it at 4266 18-18-18-38 trfc 400, 1.25-1.3 for vccio and system agent. 1.4v for ram. and it was stable and decided to start tweaking it more.
> 
> I reset trfc back to auto and took the timings to 16-17-17-37 and raised voltage to 1.45 for the ram. After about 300% coverage in karhu I got an error. Restarted, raised the voltage, got an error about the same time. Then on the third reboot Windows would not reload and I could not repair it via command prompt or automatic repair. I could not system restore either, it would just blue screen if I tried to continue. I think the code was 0xc00021a.
> 
> So I reinstalled Windows no big deal, needed to do it anyway. I backup all my important stuff regularly, and I went back to the timings I had originally and tested overnight no errors.
> 
> I've never actually corrupted my OS from tweaking ram, what did I do wrong and is there anything I can do to prevent this in the future?


Use a bench SSD drive (SATA ssd drives are easiest for obvious accessibility reasons) with a bench only OS and boot from that when overclocking and select that as the boot drive before you start tweaking.

And if you EVER get an error about 'windows can't load' and it asks you to repair it, ALWAYS power off and reset the CMOS. Most of the time your OS is still going to work as long as you didn't make it attempt automatic repair (after the error) when you're unstable. It's very unlikely that you corrupted windows by getting an error in Karhu itself but rather after the next reboot when you tried to repair the error with unstable RAM.


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## TwoCables

Were *you* restarting Windows? Or were those unexpected restarts?


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## aDyerSituation

I was restarting windows. And I did clear the cmos at one point but I'm pretty sure it was after I let windows try to repair.


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## StAndrew

I always make a restore point before overclocking and disable all HDD caching.


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## munternet

aDyerSituation said:


> I was messing with my ram timings on my patriot 2x8 4400cl19 kit
> I had it at 4266 18-18-18-38 trfc 400, 1.25-1.3 for vccio and system agent. 1.4v for ram. and it was stable and decided to start tweaking it more.
> 
> I reset trfc back to auto and took the timings to 16-17-17-37 and raised voltage to 1.45 for the ram. After about 300% coverage in karhu I got an error. Restarted, raised the voltage, got an error about the same time. Then on the third reboot Windows would not reload and I could not repair it via command prompt or automatic repair. I could not system restore either, it would just blue screen if I tried to continue. I think the code was 0xc00021a.
> 
> So I reinstalled Windows no big deal, needed to do it anyway. I backup all my important stuff regularly, and I went back to the timings I had originally and tested overnight no errors.
> 
> I've never actually corrupted my OS from tweaking ram, what did I do wrong and is there anything I can do to prevent this in the future?


@Falkentyne has some good ideas re alternate boot drive  
I like to clone my entire drive to a sata drive now as a backup using Acronis prior to pushing the ram.
I used to clone M.2 to M.2 running Acronis from a USB but the transfer is too fast and overheats the drives, hence now using sata. 3 min OS restore vs 15 min
Use GSAT immediately after making changes to the ram as it will detect OS corrupting errors the fastest in my experience.


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## kiriakos

aDyerSituation said:


> I've never actually corrupted my OS from tweaking ram, what did I do wrong and is there anything I can do to prevent this in the future?


Golden Rule = No more than 5% CPU OC when RAM this is set at tightest latency.


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## Offler

1. Do not install any windows updates when doing extreme overclocking, and be sure that all updates are suspended.
Unfortunately last builds of Windows do small incremental updates on background.

2. Disabling Drive caching might help to lower the risk.

3. If system is unstable on when doing experimental OC, any repair options are out of question.
Sometimes its better to hard-reset/crash system than let it power off, than let it save anything.


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## Veii

Windows SysMain service is there to rebuild the OS ~ and mostly does random DPC calls
The current loaded .dll & .exe files corrupt, f you stack bluescreens 
This happens simply because something accesses them & keeps them loaded 

The same goes for the OS
After a bluescreen, SysMain service will try to rebuild the OS and check it's integrity
It does nothing good most of the times, as you bluescreen likely again , before it can repair itself ~ soo that turns from "a random crash" to a "corrupted file because of multiple crashes with access to it"

Disable it, and you will have less problems
+ the OS still can repair itself after time. This service increases the corruption chance by quite a bit


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## Blameless

You can minimize the amount of writes Windows does during start up, and refrain from attempting to repair it on an unstable OC, but the only remotely sure way to prevent an install from corrupting itself is to not let Windows boot up or be used with significantly unstable settings. You can have a separate testing install, as others have mentioned, or you can simply boot to a Linux live image and do your preliminary testing from there. Even before that, I'd recommend being able to pass several Memtest86 tests 6-8.

Also SysMain isn't there to rebuild the OS itself; it's the superfetch functionality and does a lot of performance logging and preloading, which is I/O heavy and prone to corruption. Drive prefetch is mostly worthless since decent SSDs became the norm and I consider it and SysMain itself wholly unnecessary on modern systems. So, I disable the prefetcher, remove rdyboost from the list of required start services, and delete SysMain and rdyboost entirely. However, this is not a substitute for making sure the system is mostly stable before booting into Windows.


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## SmOgER

All that being said about how to prevent future OS corruption, I think you'll find it stable at 17-17-17-37. CL16 might be reaching a bit too far unless you sacrifice other timings and that's often more work than it is worth.


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## cstkl1

backup image. 
copy whatever documents, ss etc
restore image
copy back


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## aDyerSituation

Thanks for the info/input!


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## cstkl1

aDyerSituation said:


> Thanks for the info/input!


recommend using paragon uefi usb backup


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## Xtreme512

Isn't it good to use a bootable stress test software (Memtest86 and Memtest86+) when OC'ing RAM? No need to boot Windows etc. so you wont brick it.

edit: or at least use it to check few minutes if OC is OK and then you know you can safely turn on Windows to use your ram benchmark.


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## kiriakos

Xtreme512 said:


> Isn't it good to use a bootable stress test software (Memtest86 and Memtest86+) when OC'ing RAM? No need to boot Windows etc. so you wont brick it.
> 
> edit: or at least use it to check few minutes if OC is OK and then you know you can safely turn on Windows to use your ram benchmark.


This is not a bad advice but neither it is correct.
Memtest this is a single software with small complexity to be made.
All other software out there this is imperfect and makes small errors which a SIGNIFICANTLY OCed system this is unable to forgive and crash, and files corruption this in unavoidable.
*What a computer system this is all about ?*
READ and WRITES of data continuously in the unit of time.


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