Intermittent boot error that I don’t know how to diagnose

Hi,

I have an ASUS Z97-A board, with the ‘Wait for F1 if error’ option, enabled in the BIOS by default. A couple of months ago, the computer intermittently started having a problem that caused it to ‘wait’ as indicated by the option. I can F1 into the bios setup, and 9 times out of 10, if I then restart from BIOS the system boots into Windows with no problems. The 1 time out of 10 the problem repeats, another F1 into the bios almost certainly allows the system to boot.

I know a bit about computers, and have built the last 4 that we have owned. However, I have no idea how to diagnose this issue. I’ve gone into the BIOS settings to see if I can spot any obvious problems but can’t see anything off-hand. I am aware though that this is an area I lack expertise in so might be missing something. The fact it is only an intermittent problem makes it more difficult to resolve.

Can anyone give me guidance on how to go about diagnosing and hopefully fixing whatever is causing this to happen?

For reference, my system specs are:
Intel i5-4680K unclocked
Z97-A motherboard
32GB DDR3 Kingston RAM
GeForce GTX 970
Windows 8.1 64-Bit

Thanks in advance for any assistance,

Phil
10 answers Last reply
More about intermittent boot error dont diagnose
  1. I would pick up a cheap system board speaker and see if it gives any error codes, it doesnt look like there are and LED or display on the board that would show you what the error would be.

    My nest thought would be to up the QPI/DRAM Core Voltage just a little since your running 4 sticks and max amount of ram
  2. Wibbs said:
    Can anyone give me guidance on how to go about diagnosing and hopefully fixing whatever is causing this to happen?

    Your motherboard has POST state leds. You can use those to identify the problem.
    Manual page 1-36.
    https://www.asus.com/us/Motherboards/Z97A/HelpDesk_Manual/
    Also during post process there might be post state codes displayed on screen.
  3. SkyNetRising said:
    Wibbs said:
    Can anyone give me guidance on how to go about diagnosing and hopefully fixing whatever is causing this to happen?

    Your motherboard has POST state leds. You can use those to identify the problem.
    Manual page 1-36.
    https://www.asus.com/us/Motherboards/Z97A/HelpDesk_Manual/
    Also during post process there might be post state codes displayed on screen.


    Thank you - I hadn't realised that. I'll check them the next time the problem occurs and see if it tells me anything.
  4. Okay, so after what seems like an eternity, the system finally decided to play up again. I don't know why it stopped being a problem for a while. I did give the whole thing a good clean, which may have helped.....Anyway.

    On boot both the DRAM_LED and Boot_Device_LED lights were on. Does this suggest its a RAM issue?

    I had a look at the readings in CPU-Z for the RAM settings and noticed something a little odd. The readings for one of the 4 sticks of RAM is off compared to the others. The full readings are:

    Freq 837 888 888 888
    CAS Lat 9 10 11 13
    RAS to CAS 10 11 11 11
    RAS Precharge 10 10 10 10
    tRAS 27 29 29 29
    tRC 38 40 40 40
    Voltage 1.5 1.5 1.5 1.5

    Based on this new information, I would be extremely grateful for any further guidance.

    Thanks in advance,

    Phil
  5. Wibbs said:
    On boot both the DRAM_LED and Boot_Device_LED lights were on. Does this suggest its a RAM issue?

    Yes, possible.
    Can you post screenshots from CPU-Z memory and spd sections?
    (use imgur.com or tinypic.com to upload images)
  6. No problem. Here are the screenshots:

  7. Your ram has max spd values for 1777mhz rating, but you're running it at 1866mhz.
    Current latency timings are 10-11-10-30.
    Try increasing them to 11-11-10-30. Check if problem persists.
    If necessary increase timings more to 13-11-10-30. Check again.
  8. That's odd, as I haven't made any changes to the RAM settings in the bios since I bought the computer. Would it be easier to drop the Frequency back to 1777?
  9. First try with increasing latency timings.
    If that doesn't give the desired result, then you can lower frequency.
  10. Time for another update....

    I did the initial tweak, changing the CAS Latency from 10 to 11. For a few days it seemed to have helped. However, yesterday when I started the computer up it did its thing.

    What I wanted to note was that I noticed something odd when I had to go into the BIOS to get it to start. I went into the RAM timings to make the second adjustment from 11 to 13, and saw that it wasn't showing the first adjustment I'd made. This is really strange, as I made absolutely certain that the first adjustment had 'stuck' when I did it, restarting the computer several times just to be sure.

    The same thing happened this morning - the computer didn't start properly, and when I checked in the BIOS it wasn't showing the CAS Latency adjustment I'd made.

    Is now the time to reduce the frequency, or does the fact that the BIOS changes don't seem to be being applied when the computer fails to start properly an issue that alters things?
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