Computer starts briefly, then powers down and won't restart
Computer starts briefly, then powers down and won't restart
This situation is quite annoying and costly. Let's begin from the start.
About a year prior, I finished assembling the most efficient PC I ever built. It featured an Intel i9-14900K processor, an MSI RTX 4090 graphics card, 2x32GB DDR5-5600 RAM modules, four KingSpec NVMe SSDs arranged in a RAID0 configuration, a 360mm Arctic AIO cooler, an additional 1TB HDD, and three optical drives (likely irrelevant). The setup came with an MSI Z790 Pro WiFi motherboard, a large vintage Cooler Master enclosure, and a 750-watt Corsair power supply that was underpowered—this was swapped later as described.
Initially, the system performed exceptionally well for several months. However, there were recurring problems: when I pressed the power button, the machine would fail to start and required multiple attempts before it finally turned on. I suspected this was due to a worn power button or some unusual motherboard behavior. The overheating of the PSU became a concern, especially during heavy usage. Eventually, after months of intermittent shutdowns, I replaced the PSU with a significantly higher-wattage MSI model. But over time, the issue persisted, and the computer would occasionally shut down abruptly without warning after prolonged use.
I installed the new PSU, but nothing changed. The situation worsened, and eventually, the machine stopped booting or entering POST mode entirely. I replaced the motherboard, which also resolved the problem. However, this only delayed the inevitable.
Over time, I began disassembling components one by one. After thoroughly removing everything—including the case—I still experienced the same behavior: the system would start briefly, then power off and repeatedly restart. BIOS checks confirmed normal temperatures (under 35°C).
I eventually gave up on MSI motherboards, opting for a Gigabyte AEORUS X870e board paired with a Ryzen 9 9950X processor. The setup worked well initially for about ten minutes before shutting down completely. Even after unplugging the power supply and allowing it to cool for at least 15 minutes, the system would immediately power off again. I also tried removing storage drives, but no improvement was seen. A new CPU cooler was offered for free, though thermal concerns remained unresolved.
At this stage, all that remained of my original configuration were the case and memory modules. The same issues appeared even when memory was removed. I wanted to stop replacing parts and suspected the motherboard or CPU might be faulty. I avoided installing new RAM since it was costly, and I was curious whether the problem persisted without it.
I attempted to run the system without a case, but the same symptoms continued—issues with fans, front I/O, audio headers, and case controls. I also reused the old PSU, which failed again.
I reached out to a few local repair shops for advice, but received no response.
What are your thoughts? Are there any other steps I should consider? I just want to enjoy my games and write papers on a desktop once more!
Wait a moment, using a 750 W PSU for a RTX 4090 with a 14900k chip? That seems unrealistic. The suggested power rating should be around 1200 W or more. It makes sense the PSU is overheating. Probably you haven't damaged anything yet, and the crashes are just because it can no longer handle the load.
Following the previous points, I would also recommend inspecting the electrical outlet and the circuit that powers the computer.
I replaced it with a higher wattage unit as mentioned later. The issues now appear with another motherboard, CPU, and so on, and everything was detailed in my first post. It seems my updated PSU is 1200 watts.
What are those "higher wattage one" specifications?
I'm not entirely sure about the changes. It seems like something might have gone wrong after the initial setup.
The main power source remains unchanged, as per the recent updates.
Are there any extension cords, power strips, surge protectors, or UPS units connected to this circuit? Any other devices sharing it?
It's possible a ground loop could be the issue.
I attempted without a power strip; at first these issues appeared in my previous apartment, which sometimes had unstable power. I paused my computer revival project until recently, moving in August. The circuit is in my bedroom. It shares space with a table lamp, two monitors, a USB charger, and an alarm clock—nothing else comes to mind. There’s no obvious common mode or RF interference that could affect the switching power supply, based on my tests.
I’ll examine the newer model when I return home. It has never seen the computer under real load before it only briefly displayed the BIOS screen before shutting down.
MSI A1000G PCIE5 is a 1000-watt unit, not 1200. If I fix the computer, I might replace it with a 1200 watt model, but it shouldn't cause problems unless it's under heavy use.