Memtest86+ Returns After 9-Year Hiatus With Support for the Latest Hardware

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MemTest86 froze/halted in the middle of test. Is there something wrong with my system?

System freeze/halt tin be the result of several possible causes:

  • Bug in UEFI BIOS firmware (Most common cause)
  • Bad RAM & other hardware
  • Bad retentivity map configuration


If the freeze occurs in MemTest86 just the system runs unremarkably otherwise, the trouble maybe with the UEFI BIOS firmware. UEFI is still relatively new and there are numerous known bugs with specfic systems.

Bug #i – Multithread support.

The most common issue is when running MemTest86 using multiple CPU cores (default behaviour). There is a forum post that tracks known motherboard/BIOSes with problems running using multiple CPU cores. If y’all believe this event is related to the UEFI BIOS, please send a copy of the debug log to PassMark Software. This type of bug tends to exist very repeatable (not random)

Bug #two – 32bit support but.

Another BIOS issues nosotros have seen is some old Dell machines take a 32bit addressing bug that prevents testing more than 4GB of RAM. In this case testing will freeze early on during Test 0 (the address test), while exam in the 0x100000000 (4GB) memory range. To partially piece of work around this result you can limit the maximum address to test to below 0x100000000. This might mean a lot of RAM doesn’t get tested however. Or contact the motherboard vendor and ask for updated BIOS. Annotation that this can occur on CPUs that have full 64bit support. It is a merely a BIOS result.

Bug #three – Supermicro motherboards.

Supermicro motherboards have a drove of bugs. Some have the multi-threading issue detailed above. Others systems have a buggy Supermicro PCIe network carte du jour based on Intel X710 with 4 * SFP+ ports. Removing the network menu fixes the problem. Other systems have a trouble in the “SMCI Redfish” software that Supermicro supplies with the board. Redfish seems to run in the background in BIOS once the automobile boots (and is driven by interupts). The Redfish software then appears to incorrectly use RAM that was already allocated to other applications and eventually locks up the system.

Bug #4 – Apple tree BIOS update (29 Oct 2020).

Apple tree released a BIOS update in October 2020 that introduced a new UEFI multiprocessor firmware bug. Calling the UEFI functions like EFI_MP_SERVICES_GET_NUMBER_OF_PROCESSORS causes a EFI Panic (a crash) in firmware. Apple are aware of the problem and information technology should be fixed in a early 2021 update.

Problems #v – Microsoft Surface laptops can’t alter screen resolution.

Some models of the Microsoft Surface production line neglect to modify video resolution from UEFI BIOS. This results in a blackness screen that can look like a crash. In fact MemTest86 continues to run, but you can’t see anything on the screen. This tin can be confirmed past looking a the debug log file.

Bad RAM and other Hardware

MemTest86 needs at least some functional RAM to kick and run. In cases where the RAM errors are very frequent (or yous get unlucky) MemTest86 might freeze, lockup or crash, somewhat at random. If the system too freezes when booting into the operating system, the problem is likely hardware related. Then replacing the RAM is a offset option. If the problem persists, the only pick is to identify and replace parts (motherboard, CPU, peripherals) until the failure is corrected.

Bad Peripherals Configuration

The BIOS in a computer maintains a retentivity map of bachelor complimentary retention and used memory. In sometime fashion BIOSs this was sometimes called the E820 map.

UEFI provides a function chosen GetMemoryMap() to go the list. The map provides a listing of available memory ranges that can be tested by MemTest86. Unavailable ranges are used by other hardware in the system using a process called retentivity mapped.

Sometimes BIOS gets is wrong and claims a memory range is available when it is in fact already in use another piece of hardware. This results in two processes writing to the same memory, corrupting each other’s data. Sometimes this tin can cause credible retentiveness errors during testing, on other occasions it can crusade a crash.