I recently purchase a 3700x as the drop-in replacement for the temporary 2200g I've been rocking the last few months. MSI billed their b450 Tomahawk as Ryzen 3000 series ready, and I have to say I disagree strongly with that marketing. I was able to ultimately get everything going last night after what should have been no more than a 15-20 minute endeavor. Instead, it took me almost 2+ hours and a little bit of my sanity.
Anyhow, I thought I'd list here what I did that seemed to clear my issues up in attempts to help anyone who finds this by googling in the days before MSI actually releases a stable bios for this.
First, I want to say I was already on the latest bios since it was released, version v18 on MSI's site. I had also preemptively downloaded the Ryzen day-1 release AMD chipset update released 7/7. My goal was simply to swap processors and heatsinks and be done.
Symptoms: After dropping in my 3700x, the MSI Tomahawk b450 would not POST at all. One of the nice features of this board is the debugging LEDs that give some indication of the error. In this case, it was telling me the CPU was to blame. I re-seated the CPU which after being powered on only a few minutes, had firmly turned the thermal pad into a very sticky paste. I should have scraped that crap off before even trying it in retrospect. Anyhow, no bent pins, plugged it back in, and same issue.
So after browsing the internet at large for people in similar situations there were two main things I learned:
1) MSI had released a beta bios that they had already removed by the time I tried to find it due to serious issues with it. I cannot recommend enough that no one attempt to find those and use them, there's a reason MSI took them down.
2) There is no Beta BIOS at the time of this writing specifically for the b450 Tomahawk; There were other MSI b450 bioses listed, but not this specific model.
So after a lot of heartache and frustration I decided that I would attempt to use the FlashBack feature of my motherboard with a USB drive. This is actually a really nice feature and I will never buy a motherboard without it from here on, though I have to imagine they'll all have this in the future. Anyhow, to do this you need a USB drive, and a second computer.
Do these things, in this order:
1. Plug the USB drive into your secondary machine.
2. FAT32 format it (NOT FAT, NOT NTFS, FAT32!!!!)
3. Download the bios from https://www.msi.com/Motherboard/support/B450-TOMAHAWK
, the one ending in v18 released 6/24.
4. Rename the bios file to 'MSI.ROM', no quotes.
5. Drop it onto your usb flash drive, it should be the ONLY thing on it.
6. Plug the USB drive into the port that your FLASHBACK uses on the b450. You do not need anything but the power connected to the motherboard to do this, that is, you don't even need the CPU, RAM, GPU or anything else in it at this time to flash it. I'd recommend having your system already in place however, because it's easier to test the results.
7. With the machine powered on and the USB drive in place, press the button on the motherboard. Within a few seconds, a red LED should start flashing near that button. While it is flashing, the bios flash is in process. DO NOT POWER DOWN, DO NOT DO ANYTHING. When the process is complete, the system will reboot itself.
MSI offers a YouTube walkthrough of this process: https://www.youtube.com/watch?v=LRyFMf0D9Lc
Now, at this time, my machine rebooted and went from the debug LED of CPU issue, to boot failure. I started googling more and found some folks stating that if you have an NVME drive as your boot or only drive, this is likely the problem. Great, so more punishment right? Well, despite that, I read other folks stating that they had to perform steps 6 and 7 a few times. Most report 3 times, however I only had to do it twice. After the second flash of the same bios v18, my machine rebooted and posted, then landed on my Win10 login screen. If you're reading this and having these issues, try flashing it again. Do not for any reason power the system down while that red LED is flashing, the utility will reboot the system itself as proof of completion, and the LED will stop flashing at that time.
It's absolutely ridiculous the nonsense I and others have had to go through, and MSI deserves every bit of scorn and negativity they get over this. You marketed these boards as Ryzen ready, but I have to say they were not. I do not see these same issues popping up with Gigabyte, Asus, or others who marketed the same thing. If this helps even one person out it was worth it. I hope MSI does an overhaul of their testing and QA division, this is unacceptable and clearly repeatable for many folks. It shouldn't have happened.
All that heartache aside, the 3700x is a beast of a cpu. Frames are up, load times are down, life is good. Time to update my signature.