memtest errors and then no more error

[sew999]

Hello dear forum. So i want about an issue with my second pc.

cpu - 4790 stock
ram - corsair 8gb 1333mhz 1.35v low v.
mobo - Asus Sabertooth Z97 Mark 2
psu - Corsair 750 Rm


if I run memtest86 and get an multiple errors within a minute. Then run memtest the next night with the same ram, and run error free for 12+ hours, whats up with that?

Yesterday memtest86 shows errors after 5 minutes of test. I repeated test and now i am in test 24 hours without errors. So errors dont back. But yesterday i get 34 errors after 5 minutes being in memtest.
But today i am running memtest86 24 hour without any errors. So it happened once.

So it can be still memory or memory controller in cpu?
I am using Memtest86 6.0

Here are the logs:

16:14:35 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DBF64, Expected: EFEFEFEF, Actual: EFFFEFEF
16:14:36 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DBF24, Expected: EFEFEFEF, Actual: EFCBEFEF
16:14:37 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DBC24, Expected: EFEFEFEF, Actual: EFF7EFEF
16:14:39 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DBB24, Expected: EFEFEFEF, Actual: EFEDEFEF
16:14:40 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DBAE4, Expected: EFEFEFEF, Actual: EFEBEFEF
16:14:41 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DB9A4, Expected: EFEFEFEF, Actual: EFCFEFEF
16:14:42 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DB464, Expected: EFEFEFEF, Actual: EFEEEFEF
16:14:44 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DB424, Expected: EFEFEFEF, Actual: EFCFEFEF
16:14:45 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DAFA4, Expected: EFEFEFEF, Actual: EF67EFEF
16:14:46 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DAA64, Expected: EFEFEFEF, Actual: EF77EFEF
16:14:47 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DAA24, Expected: EFEFEFEF, Actual: EFEDEFEF
16:14:49 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DA564, Expected: EFEFEFEF, Actual: EF25EFEF
16:14:50 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DA4E4, Expected: EFEFEFEF, Actual: EFE3EFEF
16:14:51 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DA0E4, Expected: EFEFEFEF, Actual: EFEBEFEF
16:14:53 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4DA0A4, Expected: EFEFEFEF, Actual: EFE9EFEF
16:14:54 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D9FE4, Expected: EFEFEFEF, Actual: EFE7EFEF
16:14:55 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D9CA4, Expected: EFEFEFEF, Actual: EFE8EFEF
16:14:56 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D98A4, Expected: EFEFEFEF, Actual: EFE1EFEF
16:14:58 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D97E4, Expected: EFEFEFEF, Actual: EFDBEFEF
16:14:59 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D9564, Expected: EFEFEFEF, Actual: EFECEFEF
16:15:00 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D94E4, Expected: EFEFEFEF, Actual: EF8DEFEF
16:15:01 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8F64, Expected: EFEFEFEF, Actual: EFC7EFEF
16:15:03 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8F24, Expected: EFEFEFEF, Actual: EFFFEFEF
16:15:04 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8EA4, Expected: EFEFEFEF, Actual: EFE7EFEF
16:15:05 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8C64, Expected: EFEFEFEF, Actual: EFCFEFEF
16:15:06 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8C24, Expected: EFEFEFEF, Actual: EF6DEFEF
16:15:08 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8B24, Expected: EFEFEFEF, Actual: EFA7EFEF
16:15:09 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8AE4, Expected: EFEFEFEF, Actual: EFEDEFEF
16:15:10 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8824, Expected: EFEFEFEF, Actual: EF39EFEF
16:15:12 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8764, Expected: EFEFEFEF, Actual: EFBFEFEF
16:15:13 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8724, Expected: EFEFEFEF, Actual: EFCEEFEF
16:15:14 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D86E4, Expected: EFEFEFEF, Actual: EFB7EFEF
16:15:15 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8364, Expected: EFEFEFEF, Actual: EFE7EFEF
16:15:17 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8324, Expected: EFEFEFEF, Actual: EF6EEFEF
16:15:18 - [MEM ERROR - Data] Test: 4, CPU: 0, Address: 17E4D8064, Expected: EFEFEFEF, Actual: EF23EFEF

[David (PassMark)]

The log does look like a real RAM error.

Where the settings the same for each test. e.g. single threading vs multi-threading?
Do you remove and re-insert any of the RAM between tests?