Solution
Will the board work with just the 8 pin plugged in?

It depends on your CPU (maybe a locked i5 will work without overclocking), but you have to read your motherboard's manual for that kind of info. Some motherboards may work with only one EPS connector plugged in but only with low end CPUs and without overclocking. In any case I still don't think that the CX450 is a good match for a Z390 board. You have to get a larger and better PSU for this platform. Having said all that if you are going to install a locked i5 CPU and a low power GPU (with one 6x PCIe plug) on this board, then that PSU will work but on the other hand those parts should be paired with a lower end motherboard and not a Z390. Good luck.
No it won't work. You need a PSU with 2 EPS connectors and that PSU has only 1. Additionally most PSUs with 2 EPS connectors are over 650 Watts and most of them are expensive. Therefore you have to get a pretty good (and expensive) PSU in order to be able to properly support your motherboard. Good luck.

EDIT: Keep in mind that even if the CX450 had 2 EPS connectors, it still wouldn't be a good match for this motherboard since the CPU (i5, i7) that you are probably going to use is very power hungry (that why the motherboard has those 2 connectors). All that without taking into account any future CPU overclocking attempts that you might make or the graphics card that you are going to install. So as you can see you need at least a good 650W (or 750W depending on your GPU) PSU and preferably at least an 80+ Gold Model for good efficiency levels.
 
Last edited:

techflame700

Commendable
Nov 30, 2018
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No it won't work. You need a PSU with 2 EPS connectors and that PSU has only 1. Additionally most PSUs with 2 EPS connectors are over 650 Watts and most of them are expensive. Therefore you have to get a pretty good (and expensive) PSU in order to be able to properly support your motherboard. Good luck.

EDIT: Keep in mind that even if the CX450 had 2 EPS connectors, it still wouldn't be a good match for this motherboard since the CPU (i5, i7) that you are probably going to use is very power hungry (that why the motherboard has those 2 connectors). All that without taking into account any future CPU overclocking attempts that you might make or the graphics card that you are going to install. So as you can see you need at least a good 650W (or 750W depending on your GPU) PSU and preferably at least an 80+ Gold Model for good efficiency levels.
Will the board work with just the 8 pin plugged in?
 
Will the board work with just the 8 pin plugged in?

It depends on your CPU (maybe a locked i5 will work without overclocking), but you have to read your motherboard's manual for that kind of info. Some motherboards may work with only one EPS connector plugged in but only with low end CPUs and without overclocking. In any case I still don't think that the CX450 is a good match for a Z390 board. You have to get a larger and better PSU for this platform. Having said all that if you are going to install a locked i5 CPU and a low power GPU (with one 6x PCIe plug) on this board, then that PSU will work but on the other hand those parts should be paired with a lower end motherboard and not a Z390. Good luck.
 
Solution
It's close. You have to read the motherboards' manual or contact the Gigabyte support. The i5 9600K has a 95W TDP and theoretically one 8-PIN connector should be enough but unfortunately Intel only list the TDP for the base clock frequencies and not the turbo clock TDP. Therefore it will certainly exceed the 95W TDP number during those turbo boosting moments and the motherboard may need that 2nd EPS connector. Finally keep in mind that this is purely theoretical and the motherboard may just refuse to start with only one EPS connector plugged in, since it may need both of them in order to fully power the VRM. Good luck.