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Possible bad RAM,but need advice on diagnosis

Last response: in Memory
February 24, 2012 3:09:51 PM


So yesterday I got a BSOD while playing a game. Windows dumped memory and restarted, but afterwards I was unable to boot windows again. Stuck in my recovery discs and ran the system recovery diagnostics, they reported failures in CPU L2 cache and RAM, and then I got another BSOD with the error "PFN_list_corrupt" halfway through the RAM check. Stuck in Memtest and it reported completely red before hanging halfway through the first test. It also reported my L2 cache status as "unknown" in the top corner. Now I am unable to boot at all; I can hear everything turning on, but there is no display.

Does anyone have any advice? I was planning to swap out my RAM, but other than that I'm not sure what other actions I can take. If I'm getting an L2 cache error, does it mean my CPU is going bad?

Prebuilt, HPE-250f, about 1.5 years old. No recent hardware/software changes.

Thanks in advance for any help.
a b } Memory
February 24, 2012 9:14:45 PM

L2 cache error means the cpu needs to be replaced.....but you need to make sure first

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a b } Memory
February 24, 2012 9:22:09 PM

Cache memory holds a copy of the most recently-read RAM addresses, enabling the processor to access the same information again without fetching it from main memory. Modern processors have at least two kinds of memory cache, Level 1 (L1) and Level 2 (L2) cache. L1 cache is built into the processor die. L2 cache was originally found on the motherboard, but later became part of slot-based processor assemblies and is now part of the CPU itself. L2 cache is 128KB to 512KB in size, much larger than L1 When the processor needs information, it checks L1 cache, then L2 cache. It goes to main memory only if neither cache holds the desired information. Because L2 cache holds a large number of RAM addresses, an L2 cache failure is serious. It corrupts data, meaning that the CPU can no longer access memory reliably unless L2 cache is disabled. Disabling L2 cache causes a huge slowdown in performance. Because L2 cache is built into the CPU, an L2 cache error that's confirmed means that you need to replace your CPU.Here are some of the ways that an L2 cache error can be reported. Systems with the AMI BIOS use 11 short beeps to report an L2 cache error detected at boot time. Windows XP displays a 0x2E DATA_BUS_ERROR (blue screen) error if L2 cache, main memory, video memory or other problems take place. 0x50 PAGE_FAULT_IN_NONPAGED_AREA can also indicate defective L2 or main memory or other types of hardware or software problems. 0x218 UNKNOWN_HARD_AREA can be triggered by defective L2 cache as well as hard disk problems.Open the Advanced BIOS setup or similar screen which contains settings for Internal (processor) or L2 cache. If ECC checking for L2 cache is disabled, enable it. ECC checking can eliminate L2 cache errors. Save your changes and restart your system. Perform the same types of tasks you were performing before. If you still have errors like those in the previous step then To determine if L2 cache is faulty, you can disable it. However, keep in mind that the computer will be much slower. Restart your system and start the BIOS setup program. Disable L2 cache only if possible (disabling internal cache disables both L1 and L2). The computer will be slower without L2 cache, so use this only for testing. Save your changes and try the same tasks you performed previously. If your system no longer displays the errors listed above, your processor's L2 cache is faulty If errors persist after you disable L2 cache, other parts of your computer are at fault. If you continue to get the STOP errors listed above, search for the specific error name or code at for more detailed troubleshooting tips. Test your hard disks with a vendor-supplied disk-testing utility. Replace faulty hard disks. Replace unsigned device drivers with signed drivers. Test memory with a standalone memory tester if possible. If not, then install different memory modules.

BUT be careful cuz improper or accidental changes to the system BIOS could permanently damage your system
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February 25, 2012 3:04:26 AM


Thanks for the explaination. It looks like replacing the RAM fixed my booting problem, and the built in recovery tools no longer report any problems with the L2 cache or RAM. I'll keep using my system and looking out for those signs you mentioned. Thanks again.
March 6, 2012 12:25:05 AM

Best answer selected by wardian.
a c 146 } Memory
March 9, 2012 4:33:34 AM

This topic has been closed by Nikorr