How do I find the Mac Pro 5,1 Mid 2010 firmware latest update

The latest version go the Mac Pro 5,1 firmware BEFORE installing High Sierra should be MP51.007F.B03. That is what you should have been running before you started. Most, but perhaps not absolutely every last one already has that version on board.

The latest version of the MacPro firmware AFTER Installing the new version required to Install and Run High Sierra is MP51.0084.B00. You need to do a specific ceremony that involves holding the power button after shutting down your Mac when the High Sierra Installer tells you to do.

CUDA 9 got whacked? That may be why my 5 month old NVIDIA card is FUBAR after High Sierra. I downloaded the latest drivers that were released 3 days ago and it still doesn't work.
And I have another problem:
My 2009 5,1 has firmware MP51.0084.B00 but with 96GB of 1066R RAM, the memory is running at 1066MHz, not 1333MHz. Is that a result of firmware MP51.0084.B00?
(I thought MP5.1007F.B03 my RAM was running faster, but I didn't take any screen shots...)

1066 RAM will NEVER run faster than 1066. You needed to have installed 1333 RAM from the beginning.

To run at the faster speeds, you must have the appropriate Westmere processors.

It is not clear whether you must also not be using every last slot (triples, not all four slots).

As mentioned by Grant you need to have RAM that is 1333MHz capable and to have the right CPU chip(s) in your Mac Pro. As an example my Mac Pro 5,1 had 1333MHz RAM but originally had 2 x four core 2.8GHz CPUs. With these original CPUs it only ran the memory at 1066MHz. I upgraded it to 2 x six core 3.06GHz CPUs and it now runs the same memory at 1333MHz.

Remember my RAM was always 1333MHz capable.

I bought my CPUs off eBay. It happened that it was easier for me to arrange to collect them in person as I happened to be travelling past the seller anyway so I could see them working in a server (not Mac) before I paid and I could see the part number to confirm they were the right ones.

As you have a 2009 model i.e. a 4,1 the process is slightly more fiddly than it was for my 5,1 i.e. 2010 model.

By the way, I forgot to mention that if you have a 4,1 i.e. 2009 model, you need to also upgrade to the 5,1 firmware in order to both support 1333MHz RAM and to support the faster CPU chips. Do this before upgrading the CPUs.

The 2009 uses lidless chips whereas the most common variety as used by the 2010 is lidded chips. In theory you can remove the lid from the chips but otherwise you have to be more careful when re-fitting the heat sink so as not to crush the chips as they will be thicker with a lid than the original lidless chips.

Note: This may only apply to dual processor models.

This article might be helpful - Pimp my Mac: MP 2009 Dual CPU upgrade experience | MacRumors Forums

This article is the definitive list of compatible CPUs for all Mac Pro models - Mac Pro CPU Compatibility List | MacRumors Forums

As you will see it also details which CPUs enable 1333MHz support. I now have 2 x X5675, if I remember correctly it originally had 2 x E5640.

I posted this video above but I'll post it again just in case you haven't checked it out. The video should give you an idea of the cost involved in the upgrade along with the process.

Maxing out a 2009 Mac Pro for $2,110.65 in 2017, 12 core cpu with 128gb Ram! - YouTube

Are you using a sm951 AHCI as a boot drive? I've been holding off on the update to get more information before i pull the trigger. I have two sm951 AHCI in my 2009 5,1 Mac Pro, which gives me great performance 1400mb/s read/write but I'm worried that high sierra update might mess with the setup. I use this computer for video editing and is my primary computer for pretty much everything. I might not even update to high sierrra as everything is working flawlessly right now.

Just want to know if anyone that has a 2009 5,1 Mac Pro updated to high seirra on a pci-e adaptered SM951 AHCI M.2 SSD. And if everything is working fine.

I had the same exact problem and I did two things (one that I know helped resolve it, and one that might have)

The thing I know helped resolve it was removing my Radeon RX 580 card and putting in the stock 5770 card that came with it. I also previously had my system disk configured as a dual SSD raid - I switched that over to a single SSD mounted via PCI and had no trouble updating. I had read somewhere that APFS wouldn't support RAID (I'm not sure this is actually true to be clear) so I took that step first but in the end, I know the graphics card made a difference.

Same problem here. I'll be testing tomorrow by swapping my non-EFI NVIDIA graphics card out with the Apple edition ATI 5770 I keep on hand for such issues...hopefully, that will do the trick.

This is the first I've heard of a firmware checksum test at boot and that's very good news indeed.

I believe the new monthly firmware integrity check is a feature of just High Sierra.😟