as I said, I found that the CPU AMD Ryzen 7 Pro 4750G is definitely NOT compatible with the motherboard Asus PRIME X470-PRO, despite Asus says it is (!!!).
First of all, I have to say that I'm the owner of an IT support company and I work with PC, servers, networking & co. from about 20 years; one of my specialties is to assemble PCs and prepare gaming builds for my clients.
You can easily verify that looking at my Facebook business page:https://www.facebook.com/ncinformaticasondrio/
So, let's go straight ti the problem I have here.
This is my original system in my office:
Motherboard: Asus PRIME X470-PRO Rev. 1.02
CPU: AMD Ryzen 5 3400G
RAM: 2x16GB (32GB) DDR4-3200 Crucial CT16G4DFRA32A.C8FE
SSD: Samsung SSD 960 Pro 500GB MZ-V6P512BW
I wanted to upgrade CPU to AMD Ryzen 7 Pro 4750G, that was signed as compatible with my motherboard on Asus website:https://www.asus.com/Motherboards-Components/Motherboards/PRIME/PRIME-X470-PRO/HelpDesk_CPU/
So I bought a new Lenovo ThinkCenter M75T desktop PC, that has that kind of CPU; first I tested the ThinkCenter, and it was ok; I was also able to take a screenshot of the CPU specifications with CPU-Z (see attachments).
The CPU is a standard AMD CPU (I though there are no "custom" CPU; in my 20 years experience I never found a CPU marked as compatible with a mainboard which was not working with that mainboard!), signed with the part number "100-000000145" on the surface (see attachments).
Then I pulled out the CPU from the Lenovo and I installed it on my system.
"Obviously" it was not working: black screen and no sign of boot when powering on the system.
I then started to check all the possibilities:
- CMOS reset
- BIOS upgrade and downgrade (I tested all the most recent versions: 5861, 5406, 5220, 5216, etc.)
- Disconnected all the not essentia stuff (SSD, hard drives, USB pen drives, etc.)
- Tried to install many dedicated graphic cards (AMD RX580, Nvidia GT 730, GTX 1650, etc.)
- Tried to install in different positions many RAM banks, together and also alone, including:
NÂ°2 x Crucial CT16G4DFRA32A.C8FE original banks (2 x 16GB 3200MHz)
NÂ°1 Samsung S0A6A2011741713C23 bank taken from Lenovo PC (1 x 16GB 3200MHz)
NÂ°2 x Corsair Vengeance CMK16GX4M2B3200C16R kit taken from my gaming machine (2 banks kit 8GB each one 3200MHz)
In all these cases the system won't boot up, always black screen.
Sometimes, between the attempts, I put in back my original AMD Ryzen 5 3400G, and the PC was booting showing the message "New CPU installed"; this should mean that when I installed the AMD Ryzen 7 4750G, somehow the system was able to detect it even if black screen.
I contacted Asus official support; they told me to check if, with no RAM placed, the system was able to detect that there were no banks installed making one long and two shot beeps; and so it was, sign that theorically the CPU should have been installed correctly .
So they told me that the problem was due to the RAMs, because they weren't on the Asus Qualified Vendor List (QVL) showing me this PDF:https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM4/PRIME_X470-PRO/PRIME-X470-PRO-Memory-QVL-Ryzen-Radeo...
At home I have a mirror system with the same motherboard and CPU, only the RAM was different:
NÂ°1 Kingston KVR32N22D8/16 (1 x 16GB 3200MHz)
AND in this case the RAM was marked as compatible on Asus QVL, for the AMD 5000 series CPUs in a different PDF:https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM4/ROG_STRIX_X570-E_GAMING/Memory_QVL_for_AMD_Ryzen_500...
Even with my home system the PC won't boot up, in all the possible combinations.
So, it wasn't definitely a motherboard or a RAM problem.
Please note that each time I put in back the AMD 4750G on the Lenovo system, this was booting fine... this to check if the CPU was accidentally damaged or not during the tests. I also tried the AMD Ryzen 5 3400G on the Lenovo, and it was working fine!
My opened Asus CaseID has the number: E21100013600-0002, but it's only visible when I'm logged with my account.
The last answer from Asus was to contact AMD (still laughing!) to ask for more information about the CPU installed on the Lenovo system (...).
Obviously I threatened them that , since I'm not very happy of this answer, next time I will think twice or more before buying an Asus product, for me and also for all my customers; I also ask to speak with someone "more qualified", but till now still no answers.
I bought an expensive CPU to find that, despite what Asus declares, It's not compatible with my system.
(sorry for my crappy english, I'm from Italy)