How to block bad memory addresses on Windows

I've known this existed for a while, but haven't needed to use it, and found a guide while helping sledge here: https://forums.overclockers.com.au/threads/pc-crashing.1346960/

Basically, it is possible to tell Windows (and Linux) to not use bad memory.

You might want to use this if your ram is out of warranty, you're lazy, you need it working asap, or you've overclocked it and only a few addresses fail memtest.


The pro version of memtest will spit out exactly what to do, but someone figured out how to do it for free.

Guide: https://forums.passmark.com/memtest...klist-in-bcdedit-using-a-memory-address-range

Tldr:
memtest spits out bad addresses.
These are not exactly the granularity window needs to block.
The basic rule is: drop leading 0s, drop the last 3 chars, and add 0x to the front.

Eg
00001900 becomes 0x1
98764573 becomes 0x98764

In Sledge's case the addresses are
22fade544 and 479aadc4

So we get 0x22fade and 0x479aa to block.

Blocking is simple in modern windows. In cmd put the following:

bcdedit /set {badmemory} badmemorylist 0x22fade 0x479aa
bcdedit /set {badmemory} badmemoryaccess no

Reboot, and that should be it. Those 2 memory blocks amounting to 2x4kb should never be used. This should make an unstable pc with bad memory stable again.

The guide above has details on proving they're not, but I'm too lazy to tldr it.

It is also possible to do this in Windows 9x for you retro guys, but it's a different method. https://www.vogons.org/viewtopic.php?p=1250792&hilit=bid bad memory#p1250792

 

Wow, that's really cool - thanks for sharing.

 

^If only this was possible with a dedicated GPUs bad memory!

 

It apparently kinda was with older nvidias.
There exists a tool that can analyse the memory and write a custom bios that disables one or more memory channels.

Obviously your memory bandwidth and size drops, but most people will take limping over dead.

 

Though my issues might just be because my RAM is XMP instead of EXPO on an AMD system...
I've set it back to default settings with no errors in memtest now...

 

Yeah, but if you wanted to go back up, and it was provable that only those 2 ram bits were unable to run at that speed, you could do the above and be fine.

And when someone else has a similar problem, they'll find this

 

Myne_h, do you happen to know which old Nvidia cards it supports up to? As I've had to get my RTX 2070 fixed recently, diagnosed which memory bank/chip was faulty using mods/mats software and bought the exact RAM chip to replace it, RAM was cheap but the soldering work was expensive!! I have 0 soldering experience

 

Iirc it was Maxwell and/or earlier.

Some people on here can do the soldering.
Ask around

 

Cheers for the info, Myne_h! Too late I already paid and the soldering work done, oh well, will keep in mind in future. I have some Quadro and Tesla's that are earlier than Maxwell microarchitecture, yet to have a single one fail tho, so reliable!

 

Thanks for this, I remember reading it when you first posted it, but actually came in handy just now.

Had a random BSOD last night (again..! had faulty RAM not even 6 months ago), ran memtest86+ this morning which found 1 address was faulty.

Have blocked it which should hopefully keep my system stable until I get around to replacing it.