How can I avoid problems with CPU power?

Your CPU is not compatible with your motherboard. It is from a previous LGA1151 generation and your new motherboard chipset does not support this CPU.

Your Intel i5-7400 processor is a Kaby Lake processor which is not compatible with the 300 series chipset on your motherboard. You will need an LGA1151 Revision 2 CPU, something from the Coffee Lake range. An equivalent CPU would be either an i3-8100 or an i5-8400. Either of these would be an improvement over what you currently have (and would actually work).

See this chart from the Wikipedia Article on LGA1151 processors:

https://en.wikipedia.org/wiki/LGA_1151

You can also verify this by checking the CPU Support page listed on your motherboard manufacturers website:

https://www.gigabyte.com/Motherboard/Z390-M-GAMING-rev-10#support-cpu
(Unfortunately the table is too large to screenshot, however the minimum currently supported i series CPU is the i3-8100t)

Michael Frank

Posted 2018-12-30T20:59:34.937

Reputation: 7 412

14Even with a compatible socket, and the CPU fits, it's still a no-go. Disappointing that cpu's don't follow the cat rule "if it fits, I sits." Interesting, +1 – Xen2050 – 2018-12-30T22:38:51.427

11The reason this is happening is that the PCH (Platform Controller Hub) on the motherboard is very tightly coupled to the CPU microarchitecture nowadays. Adjusting the physical characteristics of the CPU every year is unnecessary and would add cost for Intel. So we're left with physically and electrically compatible CPUs that don't work because the PCH is too old. Newer PCHs can generally handle older CPUs, but not always. – allquixotic – 2018-12-30T22:41:03.117

1Sometimes they are specifically designed to support multiple generations depending on the tick-tock-tock cycle. – Ramhound – 2018-12-31T01:43:24.287

1@Xen2050 Nearly all (probably 99%+) of Intel's sales are to OE builders who only deal with prequalified combinations. For that ecosystem, they rather not pay the cost or the effort to retool their lines. – user71659 – 2018-12-31T02:37:48.923

1@Xen2050 This happened all the way back in the Socket 370 days. You always have to check the mobo manual or manufacturer website for compatibility. Sometimes it can be resolved with a BIOS update. Sometimes you can't. But you're always suppose to check first. – Nelson – 2018-12-31T06:50:15.520

2Intel's followed a strict 2 year compatibility block policy with CPU/chipset's for the last decade or so. While they haven't spoken publicly about why the still did a 2y break when 10nm was delayed and the released a 2rd LGA1151 generation; but avoiding a repeat of the "will it work" chaos from when they used LGA775 for ~8 years worth of CPUs which is currently being repeated with AMD's AM4 socket where many mobo makers are dropping support for older CPUs to avoid needing to use a larger flash chip to store configuration/startup data is likely. – Dan is Fiddling by Firelight – 2018-12-31T13:41:58.883

2It's probably better to just reuse the same socket but just refuse to power on, vs using a siiimilar socket (LGA115X) which kinda-sorta fits then when you clamp it down you destroy the socket and/or processor. – Nick T – 2018-12-31T21:01:56.030

7You're going to need to start troubleshooting this from the ground up. Remove any non-critical component (all but one stick of RAM, HDD, GPU) and see if it will boot. I would suggested tearing it all apart and working from scratch again, double checking all fits and connections. – Michael Frank – 2018-12-30T21:10:17.243

The same, it doesn’t matter what I connect to it. If I connect Power Supply to the CPU power on the motherboard, it will not work. Maybe this is because of some compatibility issues between motherboard and CPU? – Andrey Tsurkan – 2018-12-30T21:13:40.113

Can you confirm your motherboard model? I can't find that model listed anywhere. – Michael Frank – 2018-12-30T21:17:39.220

Oh, I’m very sorry. Unfortunately, I’ve mistyped, it’s 390 – Andrey Tsurkan – 2018-12-30T21:21:35.407

Then yes, the motherboard and CPU are incompatible. You have a Kaby Lake CPU and a Coffee Lake motherboard, while they are both LGA1151, they are different enough that they will not function together. You should take care to view the Supported CPU list when buying a motherboard: https://www.gigabyte.com/Motherboard/Z390-M-GAMING-rev-10#support-cpu

– Michael Frank – 2018-12-30T21:23:09.023

Thank you. I’ve already seen this, unfortunately, shop assistant told me that CPUs are backwards compatible. – Andrey Tsurkan – 2018-12-30T21:25:58.650

Kaby Lake and Skylake (both previous Gen LGA1151 processors) are cross compatible provided a BIOS update is available for the motherboard. Coffee Lake is not backwards compatible at all. You should take this CPU back to the store and request a replacement CPU that is compatible. – Michael Frank – 2018-12-30T21:29:03.730

19th generation hardware is backwards compatible with 8th generation hardware. 7th generation isn’t compatible with anything except 7th generation hardware. – Ramhound – 2018-12-31T01:40:51.143

How can I avoid problems with CPU power?

Answers