[SOLVED] Cold boot issues (boots fine on second boot) - PSU or something else?

martinch

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Hi all,

I built my PC at the end of 2014, and it's been running without problem (and unaltered) until earlier this month, when it failed to boot, giving an "A2" POST code (IDE Detect) and not sending a signal to the monitor. I updated the BIOS to the latest release via BIOS Flashback, which seemed to fix the issue (admittedly, I'm barely using it at the moment).

This week, when I switched it on I had the same issue - A2 POST code and no display, however, if I switch it off, wait for everything to stop (fans, lights), and switch it back on, it'll boot just fine. The gap between power-ons doesn't have to be that short (I did switch if off at the wall and waited a minute or so before switching it back on and powering it up, and it booted first time).

Neither unplugging all the SATA drives, nor removing the GPU and connecting the monitor to the HDMI port on the motherboard has made any difference (nor has replacing the CMOS battery [with a long delay between removal and replacement], attempting to boot from USB stick, cleaning and re-seating the RAM, or re-flashing the BIOS).

PC specs: Intel i7-4790K (not overclocked, XMP disabled for testing), ASUS Z97-Pro, Corsair 1866MHz DDR3, Samsung 850 Pro SSD & WD HDD, EVGA GTX 970 SC GPU, 4 x140mm Fractal Design/Noctua case fans, Corsair AX 760 PSU. PC has had ~3,250 power-on hours, based on SMART data from the SSD.

Does this sound like it's PSU-related, or something else? My gut says PSU or motherboard (I've visually inspected the capacitors on the motherboard, and they don't show any signs of bulging, etc).

If there's a chance it's the PSU, I'd rather replace that first as it'll be the cheapest component to change (and new motherboard means effectively new PC, so I might as well get a new PSU to go with that). Are there any recommendations for a replacement? I can easily get (although happy to consider other options):
  • Seasonic Focus GX: 650W (£85), 750W (£85)
  • Corsair RMX: 650W (£110), 750W (£100)
  • Seasonic Prime GX: 650W (£130), 750W (£150)
I'm assuming the Seasonic Prime isn't worth the extra money...

Thanks :)
 

Colif

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with fast startup off, there shouldn't be any difference between 1st boot and a restart.

my last PC was
Intel I5 4690K - Asus Z97 Pro WiFi - Asus Strix GTX 980 - 16gb Corsair DDR3 - Samsung EVO 850 250gb SSD - Seagate 2tb HDD - Seasonic 750 Watt Gold+ PSU - Silverstone FT02

So PC is familiar.


I doubt you would need a Prime, one of the top 2 PSU would be enough (depending IF you upgraded GPU if you had to replace more parts)
 
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martinch

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Colif

Win 11 Master
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Jun 12, 2015
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with fast startup off, there shouldn't be any difference between 1st boot and a restart.

my last PC was
Intel I5 4690K - Asus Z97 Pro WiFi - Asus Strix GTX 980 - 16gb Corsair DDR3 - Samsung EVO 850 250gb SSD - Seagate 2tb HDD - Seasonic 750 Watt Gold+ PSU - Silverstone FT02

So PC is familiar.


I doubt you would need a Prime, one of the top 2 PSU would be enough (depending IF you upgraded GPU if you had to replace more parts)
 
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martinch

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Heh, yeah, just a little bit of a similar-looking build :)

I doubt you would need a Prime, one of the top 2 PSU would be enough (depending IF you upgraded GPU if you had to replace more parts)
Thanks - I was leaning towards the RMx as I'd heard it was a bit better quality than the Focus, and the Prime felt like way too much money. I get the feeling that there's no bad choice, though! :)

I'll admit, it feels a little odd that the larger-capacity model is cheaper than the smaller one, but hey - 550W would be fine for my current PC, as well as what I'd replace it with (probably a Ryzen 7 5700X or Core i5-12600 with an RTX 3060 or RX 6600 XT [most of the games I enjoy these days aren't overly-demanding, although I would be wanting to play Metro Exodus and S.T.A.L.K.E.R. 2]), but the 750W model is £10 more and I think would always run in passive mode, and thus be nice and silent. :)
 

martinch

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A (somewhat late) update - I ended up picking the RMx over the Seasonic FOCUS on the basis that the reviews said it was better, and there was a marginal difference in price. It does seem to be very good, although the primary power cables are awful (they are incredibly inflexible due to heat-shrink cover over the inline capacitors near the connector, which really should be at the other end of the cable/in the middle, IMHO), to the point that I picked up the cable upgrade set (a massive improvement), so in hindsight the Seasonic may have been the better choice financially (returning the Corsair unit wasn't possible).

After putting a new PSU in, it turned out that either the motherboard or CPU had failed, so it's forming the basis of the new PC - at least I know it should last well! :)
 

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