PC with 1 (out of 2) cpu power cables connected. Bad?

[Andrius227]

So yeah i just build myself a new pc, but i reused the cpu cooler from the old one. When i removed the cpu cooler from my old pc, i got a clear view of the motherboard (RAMPAGE V EXTREME) and i noticed that there is an empty 4 pin connector labeled 'EATX12V_2'. I dont remember if it was like this from the very start or if i forgot to plug it in when i replaced stock psu cables with fancier ones. Anyway, i have been using that pc like this for years and i wonder if it's bad for it in any way.

I guess thats the reason why i could not overclock my cpu (i7-5930K) to even 4.2ghz? I assumed i was just bad at overclocking or something. I didnt really need more speed either so i just gave up and kept it at 4.1ghz, which was still plenty for even the most demanding games.

Anyway, i want to keep that pc as a backup and i wonder if i should look for the missing cable or if it's ok to keep it like this? I mean it's already got an 8 pin cpu power cable (EATX12V_1) plugged in so maybe thats fine?

[Omega]

A single 8 pin is enough. The extra 4 pin is not required.

[Cloudy]

It probably wouldn't damage anything, although may stop it from getting enough juice. Just like how you said you failed to overclock it... If you can I would suggest finding the other CPU power cable, but not a big deal.

[Omega]

The single 8pin can already deliver 380W IIRC. There really is no need for the other 4pin, that extra 4pin is only there for marketing reasons because more = better.

[Cathulhu]

4pin 155Watt, 8pin 235 Watt

5930k has about 187Watt under load, so there's still a lot of room to work with. More than the CPU would survive.

One 8pin is fine.

[SeriousCCIE]

hmm i used both eatx12v_1 plugged in and thwn the motherboard I had with a 4930k also had two 4-pin 12v "molex" connectors, specifically used to provide additional power to the PCIe slot areas (the board has 7 slots).

I got the CPU overlocked to 4.4 with temperatures I was fine ignoring and 4.6 at temperatures I had to pay more attention to.

When I had played uh warhammer vermintide 2 on a free weekend, the pc rebooted due to power concerns; it was the CPU drawing too much power (the event log had started to record kernel power events, the motherbaord did some throttling, and then poof. not enough to keep it up and running).

Turns out that up until then I hadn't been taxing it enough to cause an issue. This wasn't the video card drawing too much power, it was the cpu/ram area on the board.

To fix that, I actually had to use one of those adapters to plug into the open outlet, but that didn't truly provide ENOUGH power--since that just split the load off one connector into two connectors. My issues were resolved by getting a power supply that provided enough cabling options to not be missing anything.

It is unlikely I would have had the issue had I not been running the cpu a good 1200mhz faster than the rated speeds paried with 64gb of ram.

In my case, that 4930k is a backup now, just like what you are proposing. I recommend you find the cable, because if you've got that good of a backup system, changes are you'll be profoundly upset when your primary system crashes one day and you need some sort of plan B to use while trying to recover or salvage what your primary system is supposed to do.

sometimes that takes longer than we'd like to admit. You won't want plan B to fizzle on you shortly after you resigned yourself to using it.

That's just me, of course... you could drop the OC on it to stock values and truly make it a failsafe system. But if you are like me, you'll still keep trying to get performance out of it even if it doesnt see frequent use.

Note that I did not record the wattages on the 4930k as the problem happened--I was gaming, it rebooted. i had to rely on the event log, and really, I had a limited window of time because FREE WEEKEND and I normally don't bother with that stuff.

Fortunately I had another psu handy from a previous, but bigger, build, and went from a 850 watt that didn't have all the cables I needed and extras I didn't, to a 1500 watt that had cables and then some for everything I had and didnt have. Unfortunately they were not interchangable; I couldn't steal cabling despite both being modular.

It could very well be the PSU flaked out or something, but I've since reused that same PSU elsewhere without issues. That leads me to believe you still should find the cable, but by no means stop using it as a secondary--just don't push it as hard if you're concerned or never find the cable.

[tacoshy]

Автор сообщения: Cathulhu

4pin 155Watt, 8pin 235 Watt

5930k has about 187Watt under load, so there's still a lot of room to work with. More than the CPU would survive.

One 8pin is fine.

it will survive higher wattage as the volatge is important and its fien up to 1.52V whiel it easiyl reaches the 187W under laod at 1-1.1V.

If you overclock the extra 4 pins become mroe important. Thats why those motherboard have thsoe pins in the first place.

[_I_]

the eps was first used when intel decided that the (pentium 4) cpus power should have their own dedicated power rail from the psu, not sharing the 12v rail with the drives, fans ect which can add electrical noise in the line

but newer power supplies make cleaner power than the old p4 versions and can share the rails with other devices without issues

[ericcui1]

The 8 pin EPS connector was designed to deliver at least up to 384W. Plenty of headroom for overclocking your 5930K. Even 9900K does not go that high unless under exotic cooling (LN2 or chilled water).

[_I_]

there is no logical reason for any mainstream single socket mobo to have 2x 8pin eps connectors
iv seen a few that use a molex for the pci-e slot power, but not both for cpu