MP 1,1-5,1 MacPro 3,1 64 GB Ram GTX 680 Mojave - Complete System Slowdown

[bigfoley]

MacPro 3,1 / 64 GB Ram, 120 GB OWC EXTREME PRO Sata SSD APFS, 2GB GTX 680 / DosDude Patched Mojave 10.14.6 - Complete System Slowdown when I put in 64GB of ram. The system comes to a crawl on boot. Even using the browser is unbearably slow, cpu usage is off the chart.

I did use the following boot arg when I had 24 GB of ram in the system per the instructions in a previous thread: sudo nvram boot-args="maxmem=63488". After entering the command I shut down and then inserted the 64 gigs of ram (all matching) and rebooted, all i got was an ultra slow system again with 64 GB of ram. If I enter the command again with the same arguments with 64G in the system, I get the same slow result again.

If i have only 24 gigs of ram in the system it works fine and it is snappy. Can anyone help?

 

[mikas]

It could be related to your 64GB RAM. Maybe you have read all of that already, if not, here you go:
cMP 2008 + 64GB MEM = SLOW DISKS while 48 GB = FAST DISKS; why?

 

[joevt]

Yes, 64 GB of RAM causes a slowdown in macOS and Windows. There are ways to fix it.

Mac Pro 3,1 NVMe support + Upgrade Guide + Questions

64 GB slow down problem and Windows 10: I was having problems booting Windows 10 with 64 GB #460 . I think it was just taking a long time. Once it finished booting I was able to use EasyBCD to edit the bcd (you can use bcdedit) and deduct 2048 MB from the RAM. I used CPU-Z to run benchmarks...

forums.macrumors.com

Mac Pro 3,1 NVMe support + Upgrade Guide + Questions

Hello everybody! I'm newly owner of MP 3,1 and I want to discuss upgrading of this nice but old machine with you. I suggest everyone to take part in creating this guide. Now I will post my achievement in making it bootable from NVMe SSD. Bootable NVMe Note: it can be dangerous for your MP...

forums.macrumors.com

If you want to install Catalina, be aware that the current dosdude1 patcher will remove maxmem from boot-args causing it to slow down. There is a patch:

boot-args fix by joevt · Pull Request #103 · dosdude1/macos-catalina-patcher

Here is a change that helped me update Catalina to 10.15.7. The patch does not replace boot-args NVRAM variable. It will append to it or create it if necessary.

github.com

 

[jtsay]

I need the fix in Pull Request #103. How do I get it?

 

[joevt]

I need the fix in Pull Request #103. How do I get it?

You can try downloading the source code, applying the change, and building it. The change is small so you could do it manually.

Go to the link, click Commits, then click on each commit to see what was changed. Copy and paste the change into the code you downloaded. There's probably a GitHub command to do all the above but I'm no GitHub expert.

Build it.

If you already have a patched installer, then you can replace the files on the patched installer with the file that contains the change (I think they are apfsinsta, apfsbless, runposti).

 

[jtsay]

Thank joevt's prompt reply. Since there's only file got modified:
macOS Catalina Patcher/apfsinsta/SystemPrep.m
I manually change and build it. It looks like only apfsinsta got built. I'm testing it from build directory at the moment. It will take a few hours to know for sure but so far so good.

 

[joevt]

Thank joevt's prompt reply. Since there's only file got modified:
macOS Catalina Patcher/apfsinsta/SystemPrep.m
I manually change and build it. It looks like only apfsinsta got built. I'm testing it from build directory at the moment. It will take a few hours to know for sure but so far so good.

Is there a build all option? Not an Xcode expert.

 

[jtsay]

I use Build menu item under Product. You need to remove signing otherwise the build would fail.