PSU or motherboard issues?

[Insatri]

Good day everyone!


I'm having some serious issues with my computer, and I can't really pinpoint the root cause. It's an older build, though good enough to play games such as Destiny 2 or the recently launched Black Ops 4 at almost max details in 4K; this of course after buying the 1070 GTX card last year:

MB: MSI Z77A-G43
CPU: i7 3770K @4Ghz (Cooler Master Hyper 212 EVO cooler)
RAM: 2x 8GB Patriot 1600 Mhz (running at 1866 Mhz)
GPU: Asus 1070 GTX
PSU: Super Flower Leadex Gold 750
Other: 1x 120 GB SSD, 1x 1TB HDD, DVDRW and a case fan

It all started a few weeks ago when I was trying to turn on the PC, and even though there was power since I was hearing the HDD and DVDRW specific sound, as well as seeing the fans spinning (or the LED lights in all their colourful glory) - nothing appeared on the display. I ignored the behaviour since it was occurring maybe once every 15-20 times I was using the computer. I started to monitor the problem after it accelerated quite fast, being now in the opposite pole where maybe it boots correctly after 50-60 tries.

To be more specific, the white lights from my PSU cables are visible and like I said, it "feels" everything is powered on (including the CPU, GPU and case fans). Also tried the on-board HDMI. I realised it might be from the motherboard after noticing my RGB keyboard, headset and wireless stick are not working, the USB ports having no juice. I tried all combinations with our without the RAM, removed and put back the MB, checked all the cables, tried to boot with less items (HDD, case fan, DVDRW) - no luck. I was almost ready to place an order today for a new 2700X PC when out of the blue I said well, let me try once more. And it worked properly! I then checked the voltages, and the 3.3 is really 3.3, the CPU one is around 1 and the 12V rail stays at 11.97. I made sure to enter the BIOS and revert any OC. Of course, it was a once-only occurrence since now it doesn't want to "start" anymore.

I'm literally out of ideas. Any feedback is greatly appreciated, though to be noted I don't have another PSU to try.

Much appreciated,
Antonio

 

[Araxie]

Always start by the PSU it may be the +5VSB, (typical issue on older PSUs) also the 12V at 11.97 under no load on a high end high quality PSU as yours is not anything close to normal..

 

[hititnquitit]

11.97 is well withing specs. 5% up or down is the standard so your good there. thats a really solid unit. if its really old it could always be the cause but with no way to test it your stuck. tbh i think your on the right track. i would lean more towards the mb slowly dying on you. if possible i would pack it up and head to the closest pc shop. you can usually get them to test gear for you for next to nothing.

 

[TheFlayedMan]

You could buy a 2nd hand Z77 motherboard for not too much money.

 

[Insatri]

Many thanks for the replies, as well as the related suggestions!

Luckily I had a friend who brought two PSUs together with his current PC and after several (yet, thorough) tests it's clear the MB was indeed faulty. To be honest, I've thought about buying a second hand Z77 motherboard - but I just took advantage of the situation and acquired the following:

• MB: GIGABYTE Z390 Aorus Pro
• CPU: Intel i5-9600K (I've kept the CM cooler)
• RAM: Corsair Vengance Pro RGB 16GB (2x8) DDR4 3000 Mhz

I've already sold my old RAM, will also put the i7 3770k for sale this weekend so I can dampen the investment. I must admit, all the pretty lights mesmerize me now, hah!

The new CPU stays at around 35 degrees in idle, reaching maximum 55-61 during full load (depends on the game). It's odd, but the RAM sits at 35-40 degrees - is this normal? Seems a bit high. Regardless, with the new "system" I'm hitting 35 - 45 fps in Black Ops 4 @4K and settings set to Ultra (60-80 fps @1400p with Ultra as well).