CPU or Motherboard issue? (IBT Pass, Memtest Pass, Prime95 Blend Fail)

[Guest]

Basically im trying to find why im occasionally getting system freezes

Tested the following:
- Intel Burn Test, all settings, pass
- Memtest 86+ v5.01, passed 24 hours worth, 0 errors
- Prime95 blend, fails around 1h 20 - 1h 40 mins, always different threads
- Other Prime95 tests, all pass 24h+

PC specs:
- i7 3770K @ 4.5GHz, auto voltage, LLC at max, 1.3v at load
- Asrock Z77 Fatal1ty Professional-M
- 16GB @ 1600MHz @ 8.8.8.24 Timings, 4x4GB DIMMs, 1.35v
- Asus GTX 770, DCII OC @ stock

I've tried increasing cpu vcore, vccsa, vtt voltages, to no luck, also tried activating XMP #2 on the dimms which puts them to 1.5v, also tried leaving entire bios at stock, also no luck, im still getting some instability during memory intensive processing

Is there anything else i should try? And what is wrong with my pc? i suspect its CPU/ mobo

 

[Guest]

Turns out this was the CPU going bad, to be more specific, the memory controller.

The i7-3770k works fine in a spare motherboard with 2 ram sticks, while the i3 3250 that was in that board, also works fine in the main pc's asrock board, with all 4 ram sticks plugged in.

Then swapped back over, but removed 2 slots from the i7, now only running 8gb, tested and pass, stable, turned voltage down to 1.35 (xmp profile 1) and it was still stable.

Came to the conclusion it was the memory controller in the i7-3770K.

Now moved to a new motherboard and cpu:

Mobo: MSI Z97M Gaming
CPU: i7-4790K @ Stock

All 4 ram slots work in that, and performance is even better!

If anyone wants either:
Mobo: Asrock Z77 Fatal1ty Professional-M
CPU: i7-3770K (1 ram slot per channel only is stable)
for cheaps, pm me!

 

[dfk]

Turns out this was the CPU going bad, to be more specific, the memory controller.

The i7-3770k works fine in a spare motherboard with 2 ram sticks, while the i3 3250 that was in that board, also works fine in the main pc's asrock board, with all 4 ram sticks plugged in.

Then swapped back over, but removed 2 slots from the i7, now only running 8gb, tested and pass, stable, turned voltage down to 1.35 (xmp profile 1) and it was still stable.

Came to the conclusion it was the memory controller in the i7-3770K.

Now moved to a new motherboard and cpu:

Mobo: MSI Z97M Gaming
CPU: i7-4790K @ Stock

All 4 ram slots work in that, and performance is even better!

If anyone wants either:
Mobo: Asrock Z77 Fatal1ty Professional-M
CPU: i7-3770K (1 ram slot per channel only is stable)
for cheaps, pm me!

interesting, nice diagnosing of the cpu part. I'm currently having memory problems too, having a single error in dual channel memtest86+. my i5-4590 was used when bought so i'm not sure if it should be suspect. not sure how to go around diagnosing that since i dont have any spare parts.