Windows 10 Pro slower boot from SSD #2 than SSD #1

Hey guys;
I just did a new build.

ASUS Tuf Gaming X570 Plus WiFi
AMD Ryzen 7 3700X
32GB 3200MHz RAM
Gigabyte GeForce RTX 2070 Super
Storage: 2ea WD Blue SN550 1TB; one on M.2_1 and one on M.2_2

When I first installed Windows 10 Pro, I put it on the M.2_2 disk. Why? Because there is a heatsink installed on that SSD and not on M.2_1, so I thought with the OS the one with the heatsink would run cooler.
I don't recall how long it took Windows to boot.

I was curious about whether I would get better performance if I installed Windows on SSD #1 (the one that is directly from the CPU).
Note: neither of these SSD are PCIE 4.0.

I also wanted to see if the temperature of the SSD without the heatsink would rise if I installed the OS onto it.
So, I created a dual-boot system by installing Windows on SSD #1.
Before I did the 2nd install on SSD #1, I partitioned SSD #1 into two roughly equal (500GB) partitions. I did this from the 1st install using Disk Manager.

Now, when I boot the computer, I get the Windows boot menu.
Selecting:
Windows on SSD #1: Boots to login screen in 3 seconds
Windows on SSD #2: Boots to login screen in 28 seconds.
The boot manager is installed on SSD #2.

So, I'm wondering whether having the boot manager on a different drive than the OS allows the OS to boot much faster.

Finally, I will get rid of the 1st install, but I understand that I must not delete the boot partition.
There are 4 partitions on SSD #2:
Recovery: 529MB
<unnamed.: 99MB
Disk1_0 (E:) 540.26GB (Windows is installed here)
Disk1_1 (F:) 390.62GB (this is the partition I created by shrinking the Disk1_0 (E:) partition after the 2nd Windows install.

What process would I use to remove the Windows install on SSD #2, without destroying the boot manager partition?

Thanks for your help
Ultrarunner

Did you read the MB manual? Some M.2 slots shares resources with another device.
Did you try to switch the drive x M.2 slot (put the fast drive on the slowest slot)?
If they are same brand and model how come one has a heat sink and the other doesn't?

I have solved the problem: The reason the one Windows install is booting faster, is that it is the one set as default. So, when the boot manager screen comes up, that OS has already been loaded. If I choose the non-default OS, the system has to restart, then boot into it. So actually the total time for both is the same.
I am going to remove the original install on SSD #2, but keep the boot manager on SSD #2, as moving it to SSD #1 would require a complete re-install, and there would be no benefit by doing that.

The reason only the SSD #2 has the heatsink is that's how the board came from ASUS. They only provide the one heatsink on this board, but on their premium boards they provide two heatsinks. On the lower boards, they provide no heatsinks for either of the SSD's. I have ordered a 3rd party heatsink for SSD #1.

One interesting note:
With the OS running on SSD #1 (without the heatsink), SSD #2 (with the heatsink) is running a few degrees warmer.
I'm wondering whether I didn't install the heatsink properly. I did remove the protective backing, then pressed the heatsink onto the SSD and secured it with the two screws.
I'm going to re-check it when I install the heatsink for SSD #1.

Actually, on the X570 board, I don't think the SSD shares bandwidth with anything else, but I may be wrong about that. In any case, with both SSD's being PCIE 3.0, it shouldn't make any difference.

You started wrong as you installed the 2nd windows without removing the first M.2 drive ending with a OS in one drive and the boot loader in the other.
Now you're going to make it worst.
Why don't you make a disk image of the drive that has the EFI and the Windows partition and then put in the M.2 drive you want?

Considering that I haven't done much installing of apps on this new build, I should Probably just start fresh with one install of Windows.
I can format both drives during Windows install. that way, there won't be any confusion when Windows finds the boot on the other drive.

On a Clean install, ALWAYS detach all other drives, leaving on ONLY the target drive or you may end again with windows in one drive and the boot loader on the EFI partition on another drive.

Megahertz said:

On a Clean install, ALWAYS detach all other drives, leaving on ONLY the target drive or you may end again with windows in one drive and the boot loader on the EFI partition on another drive.

Personally, I have never done that. Very seldom has the system partition the computer boots from ended up on the wrong drive, especially if the drive being installed to is completely blank with no partitions already defined on it. In the few cases where the system partition has ended up on the wrong drive, it is a very simple fix to create a system partition on the drive you want it on. I would not want to be removing an M.2 SSD just to install Windows - way too easy to drop that darn little screw and mess things up.

I agree with NavyLCDR;
The SSD #2 is installed with a heatsink which would need to be removed, destroying the thermal pad.
i now have Windows 10 and the boot loader installed on SSD #1. All is good!