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8500C5DF fails MemTest86+ when memory size is probed


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I've recently built a new PC, using Corsair TWIN2x2048-8500C5DF ram (ver1.2, 2.20V). I have installed the memory and set BIOS to run it at DDR1066, 5-5-5-15 (the advertised speed) at 2.1V. The system FSB is running at the stock speed of 333 Mhz, and I have disabled all "Performance Enhance" type options in BIOS.


The RAM passes MemTest86+ v2.00 when left with the default memory sizing (which detects 2047 MB, but reserves 86 MB). However, when I use the probe memory size option (which detects 2047 MB and reserves 0 K), it will always detects errors in test 6 at the same location (~1551mb), then freezes. Using the "BIOS- All" option reports 2131MB of ram, and finds errors at ~3840mb (!!!), then freezes. I'm quite sure the second issue is a software issue, but am suspicious about the probed result. My old PC can pass with probed memory sizing. I have also tested the RAM with MemTest86+ v1.70, failing with hundreds of thousands of errors at ~1550MB if the memory size is probed.


I am currently testing the RAM sticks individually at DDR800 5-5-5-15 2.1V. The first creates errors at 527mb when using probed sizing, and no errors when using the default sizing (84M reserved). The second creates errors at 4095mb when probed and no errors when using the default sizing (84mb reserved).


Does anyone have any advice? More volts? In the past I have had Corsair RAM replaced, only to find the errors were being caused by a BIOS setting that does not provide a disabled option (MAM on i865P).


Relevant System Specs:

Gigabyte P35-DS4

Corsair TWIN2x2048-8500C5DF

Intel C2D E8400

Zalman 750W PS

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  • Corsair Employees

Yes don't do that!

Just use the default tests unless you know exactly what you are doing!

The Probe option with a X86 system, may cause errors and that is in the read me file on the Memtest site. X86secret.org.


Many MB's and Chipsets may map the memory differently and some will reserve a small amount of ram to run from and if some application try's to access that area of memory the system may become un-stable.

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