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Should I connect the second 4 pin CPU

advapi
Level 7
Hello,
I've just left my i9 9900k for the AMD platform, now I have an Asus X570-f ROG Gaming with 3900X and I've currenly only connected the 8-pin CPU cable (+ the 24 for sure!)

I was wondering if I really need to connect the 4 pin CPU as well and what it changes .
Thanks
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Murph_9000
Level 14
It's theoretically optional, but can be required if you want to push your CPU. For example, my 5950X has a stock power of something like 105W. With PBO2 enabled and the limits raised/removed (configured as +200 boost, 395W PPT, 255A TDC, 200A EDC, -25 all core CO; everything else on auto, roughly), it can run around 150-200W with just AIO cooling (that's roughly a sustained all core 4400MHz, or sustained 4700MHz on a few cores with peaks of about 5000MHz; over the baseline stock frequency of 3400MHz). The optional 2nd power connection helps the board supply that and cope with any spikes in demand. If your PSU has a spare output that you can easily connect, do it; it can help the combination of board and chip deliver peak performance. If it's a problem to connect it, you can live without it but possibly won't be able to reach as high stable performance.

There's really no reason not to connect it if you have the PSU output and a cable to do so. It's only ever a good thing, even if you don't intend to do more than basic boost with stock limits.

wendybyrde506
Level 7
advapi wrote:
Hello,
I've just left my i9 9900k for the AMD platform, now I have an Asus X570-f ROG Gaming with 3900X and I've currenly only connected the 8-pin CPU cable (+ the 24 for sure!)

I was wondering if I really need to connect the 4 pin CPU as well and what it changes .
Thanks

Try to connect then you can confirmed

Silent_Scone
Super Moderator
Hello,

A 8-pin EPS12V CPU connector can draw over 235W. If you're able to trip OCP on a 5950X with a single EPS12V you're going in hard :cool:

In short, it's not necessary unless going sub-ambient.
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

I've connected it (it was alone in the psu box in the cellar)...for now no problem at all !

advapi wrote:
I've connected it (it was alone in the psu box in the cellar)...for now no problem at all !


AFAIK it can do no harm... at least it does nothing and you have 1 more cable to root in your case.

Baio
CASE Lian Li 011D XL CPU AMD Ryzen 5900X COOLER Corsair H150i Elite Capellix MOBO Asus ROG Crosshair VIII Extreme RAM 2x16Gb Corsair Dominator 3800 CAS14 GDM OFF PSU Asus Thor 1200P VGA Asus ROG Strix RX 6900XT DISPLAY LG 34GK950GF AUDIO Logitech G560 SDD WD Black SN850 4Tb NVMe NPUT Logitech Pro wireless + Powerplay + Corsair MM700 RGB - G513