Author Topic: Motherboard power validation  (Read 63 times)

skyllinks

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Motherboard power validation
« on: June 28, 2019, 06:51:13 PM »
My grandson and I are having fun jointly tackling your Jun 2019 $1500 build (but with July i7 9700), and would like to validate the mother board power connections. We used your recipe and have a Gigabyte Z390 Gaming X (Intel LGA1151/Z390/ATX/2xM.2/Realtek ALC892/Intel LAN/HDMI/Gaming Motherboard) with Seasonic FOCUS 550 Gold SSR-550FM 550W 80+ Gold ATX12V & EPS12V Semi-Modular 7 Year Warranty Compact 140 mm Size Power Supply. The 24 pin ATX is self explanatory, but we aren't finding what we are certain is the proper CPU power configuration. The PS has a connector which matches with the 2x2 ATX_12, but will not power on the CPU by itself....motherboard lights but no CPU power. The same connector will fit both halves of the ATX_12V_2x4 but still no CPU power. Bottom line is the PS has no additional 2x2 cable to fill the 2x2 ATX_12 as your install video shows. Do we need to source another split 2x2 cable to populate the 2x2 ATX_12V to provide the power for CPU? Or are we way off and don't need to populate both as in the video? Thanks in advance.....skyllinks

Ari Altman

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Re: Motherboard power validation
« Reply #1 on: June 28, 2019, 09:51:23 PM »
My grandson and I are having fun jointly tackling your Jun 2019 $1500 build (but with July i7 9700), and would like to validate the mother board power connections. We used your recipe and have a Gigabyte Z390 Gaming X (Intel LGA1151/Z390/ATX/2xM.2/Realtek ALC892/Intel LAN/HDMI/Gaming Motherboard) with Seasonic FOCUS 550 Gold SSR-550FM 550W 80+ Gold ATX12V & EPS12V Semi-Modular 7 Year Warranty Compact 140 mm Size Power Supply. The 24 pin ATX is self explanatory, but we aren't finding what we are certain is the proper CPU power configuration. The PS has a connector which matches with the 2x2 ATX_12, but will not power on the CPU by itself....motherboard lights but no CPU power. The same connector will fit both halves of the ATX_12V_2x4 but still no CPU power. Bottom line is the PS has no additional 2x2 cable to fill the 2x2 ATX_12 as your install video shows. Do we need to source another split 2x2 cable to populate the 2x2 ATX_12V to provide the power for CPU? Or are we way off and don't need to populate both as in the video? Thanks in advance.....skyllinks

Welcome to the TBG Forum, skyllinks!

This is actually a question that I've received several times, and anticipated getting even more often, so the guides have been updated for July so this issue can be avoided (by using a different motherboard that drops the secondary CPU power port all together). The motherboard you have is designed to provide higher overclocking limits for high-powered processors, but that requires two EPS connectors (what you're referring to as the ATX_12V_2x4 and 2x2). Alas, the Seasonic 550FM doesn't have two of these connectors, and in fact no power supply under 750W has them. It's sort of a generational mis-match, as motherboards prior to the Z390 generation never used two of these, but Intel's latest processors use a tremendous amount of power, and power supply manufacturers haven't caught up with new models. It's not that the 550W power supply can't deliver the power when used alongside the RTX 2070 GPU, it's that it doesn't have the right cables to do so.

Luckily, your motherboard should power up using the two halves of the EPS connectors (the 2x4), plugged into the 8-pin receptacle. Leave the 4-pin receptacle empty. And to be clear, this EPS connector is permanently affixed to the PSU, so it's not a matter of finding the connector in the box. No other EPS connectors is provided or can be added.

Please report back on whether you're able to get it working.