Memtest errors with XMP on only

[AJ95]

I ran a Memtest (XMP on) and it threw up errors in tests 8 & 13 (see below). I then attempted to find the faulty memory by having the test run each module individually, but with XMP off. This allowed all memory modules to go through the test without any errors. I then ran the modules individually but with XMP on, this again allowed each one to run through the test fine.

Any idea whats causing this? Could it be voltage?

Help is appreciated, thanks.
System Information

EFI Specifications	2.70
System
Manufacturer	Micro-Star International Co., Ltd.
Product Name	MS-7B17
Version	1.0
Serial Number	Default string
BIOS
Vendor	American Megatrends Inc.
Version	1.50
Release Date	03/25/2019
Baseboard
Manufacturer	Micro-Star International Co., Ltd.
Product Name	MPG Z390 GAMING PRO CARBON (MS-7B17)
Version	1.0
Serial Number	J816293218
CPU Type	Intel Core i9-9900KS @ 4.00GHz
CPU Clock	4059 MHz [Turbo: 5074.2 MHz]
# Logical Processors	16 (8 enabled for testing)
L1 Cache	4 x 64K (229204 MB/s)
L2 Cache	4 x 256K (103745 MB/s)
L3 Cache	16384K (51971 MB/s)
Memory	32714M (23337 MB/s)
DIMM Slot #0	8GB DDR4 XMP PC4-25600
	Corsair / CMW16GX4M2C3200C16
	16-18-18-36 / 3200 MHz / 1.350V
DIMM Slot #1	8GB DDR4 XMP PC4-25600
	Corsair / CMW16GX4M2C3200C16
	16-18-18-36 / 3200 MHz / 1.350V
DIMM Slot #2	8GB DDR4 XMP PC4-25600
	Corsair / CMW16GX4M2C3200C16
	16-18-18-36 / 3200 MHz / 1.350V
DIMM Slot #3	8GB DDR4 XMP PC4-25600
	Corsair / CMW16GX4M2C3200C16
	16-18-18-36 / 3200 MHz / 1.350V

Result summary

Test Start Time	2020-01-07 09:03:44
Elapsed Time	5:23:03
Memory Range Tested	0x0 - 86E000000 (34528MB)
CPU Selection Mode	Parallel (All CPUs)
ECC Polling	Enabled
# Tests Passed	40/48 (83%)

Lowest Error Address	0x9AEC1DC (154MB)
Highest Error Address	0x85E956D04 (34281MB)
Bits in Error Mask	0000000000380000
Bits in Error	3
Max Contiguous Errors	1

Test	# Tests Passed	Errors
Test 0 [Address test, walking ones, 1 CPU]	4/4 (100%)	0
Test 1 [Address test, own address, 1 CPU]	4/4 (100%)	0
Test 2 [Address test, own address]	4/4 (100%)	0
Test 3 [Moving inversions, ones & zeroes]	4/4 (100%)	0
Test 4 [Moving inversions, 8-bit pattern]	4/4 (100%)	0
Test 5 [Moving inversions, random pattern]	4/4 (100%)	0
Test 6 [Block move, 64-byte blocks]	4/4 (100%)	0
Test 7 [Moving inversions, 32-bit pattern]	4/4 (100%)	0
Test 8 [Random number sequence]	0/4 (0%)	121
Test 9 [Modulo 20, ones & zeros]	4/4 (100%)	0
Test 10 [Bit fade test, 2 patterns, 1 CPU]	4/4 (100%)	0
Test 13 [Hammer test]	0/4 (0%)	18

Last 10 Errors

2020-01-07 14:22:14 - [Data Error] Test: 13, CPU: 0, Address: 2FFD01BAC, Expected: 86D3557B, Actual: 86F3557B

2020-01-07 14:20:37 - [Data Error] Test: 13, CPU: 0, Address: 2F15AF3C4, Expected: A9FB56B6, Actual: A9DB56B6

2020-01-07 14:15:16 - [Data Error] Test: 13, CPU: 0, Address: 494DBA614, Expected: 21023698, Actual: 210A3698

2020-01-07 14:11:57 - [Data Error] Test: 13, CPU: 0, Address: 2469CD044, Expected: DB34D82B, Actual: DB3CD82B

2020-01-07 14:05:58 - [Data Error] Test: 13, CPU: 0, Address: 12941712C, Expected: 84F96A02, Actual: 84D96A02

2020-01-07 14:02:11 - [Data Error] Test: 13, CPU: 0, Address: 12A0C814C, Expected: 5279FBE3, Actual: 5259FBE3

2020-01-07 14:01:16 - [Data Error] Test: 13, CPU: 0, Address: 5E56BD1D4, Expected: C448C8E4, Actual: C440C8E4

2020-01-07 13:28:07 - [Data Error] Test: 8, CPU: 0, Address: 85E956D04, Expected: 67910C83, Actual: 67990C83

2020-01-07 13:28:03 - [Data Error] Test: 8, CPU: 14, Address: 818624E0C, Expected: 3273C996, Actual: 3253C996

2020-01-07 13:27:59 - [Data Error] Test: 8, CPU: 6, Address: 7CBB61E6C, Expected: 175E8224, Actual: 17568224

[David (PassMark)]

Is your CPU overclocked?

It isn't unusual to see RAM errors only in dual channel mode.

From the log above, it looks like the RAM is bad. See,
https://www.memtest86.com/troubleshooting.htm

[AJ95]

The CPU is a binned and 'factory OC' chip.

So it's still bad possible the RAM is bad even though individually testing threw up no errors VS testing them as a set?

[David (PassMark)]

The CPU is a binned and 'factory OC' chip.

By who? Intel?
Intel, as far as I know, are only selling them at 5Ghz. But yours is closer to 5.1Ghz.

Just wondering if whoever did the overclock tested it well enough with a variety of RAM.

Might be worth retesting at stock speeds.

[AJ95]

Yes its 'OC' at factory by Intel. The 9900KS processor is just a binned and pre-overclocked version of the 9900K. These are 'stock' or at least this is how they've been since I installed the CPU. I've had it from new and haven't changed anything personally, so I can't explain the higher figure.

[David (PassMark)]

Still seems pretty strange. As the 9900KS is already a binned oveclocked version of the 9900K. So it is factory overclock of an already overclocked CPU?

There was a 3rd party company doing this, called Silicon Lottery, and they claimed that only only 31% of Core i9-9900KS processors can run at 5.1GHz. The rest fail.
But this isn't a factory overclock.

[AJ95]

It is curious that it's turboing so high. I ran the MemTest because I've been trying to diagnose various BSOD. So I'm now wondering if this may be part of the issue, something to investigate.