HP Z600 old workstations for use with LinuxCNC

Yesterday i got 5 of Z600 workstations, as life would have after a friend gave one for free to me as i service and maintain his laptops and PC from time to time, i asked for the price as he had another 7 home collecting dust, and after quite a bit of back and forth (and bickering) we agreed on another 4 for 100 Euro total, making it 25 Euro a piece!
Wasted yesterday evening and night, and today all day testing and installing those, organizing memory modules (several types of several sizes on all of them) ended up 4 having 16GB of ECC RAM and one having 24GB of ECC RAM and some left over 2GB and 1GB modules, all have 128GB SSD and some have and assortment of spinning HDD's from 80GB to 500GB, all have old NVIDIA Quadro graphic cards that now seem pathetic compared to a GTX1060/6GB or RX580/8GB that i promptly switched to on two of them, all have 2 of Xeon 4 core CPU's at 2.4GHz, and proprietary 650W power supply with a single 6 pin VGA power connector, and all weigh in at over 20KG !!!
So far tested with Linux Mint 22.1 and LinuxCNC 2.10 on 6.13 RT kernel, all have very good latency from short test i did. Will do more tests and also add a parallel port to one to test with as they do have PCI slots.
Have to go to the shop and finish 2 more installs, so for now i leave you with this:
Do NOT buy raspberry PI, buy everything else.

OK more tests done, and frankly way to much for a day and a half, but sparing you of the long whinny road so here is a lowdown in no particular order:
-uses about 80W of power at idle with Linux Mint 22.1 running the 6.13 RT kernel, should use less with the normal kernel
-uses 350W of power while running FurMark and Blender Benchmark at the same time with GTX1060/6GB graphic card, so fully loaded
-plays 4K@60FPS youtube videos at 1.5X speed without dropping frames, BUT, hardware acceleration must be turned OFF in FireFox. This is also something i do on every new install as FireFox has dropped the ball badly there.
-6.13 RT kernel works with the included Nvidia cards with NO proprietary drivers installed, fails with black screen when drivers installed.
-6.13 RT kernel will not work (well it will, once, then black screen) with AMD RX580/8GB graphic card, normal kernel works perfectly. Not tested with proprietary ADM drivers, just the included Mesa drivers (not our Mesa/PCW )
-6.13 RT kernel works nicely with PCI to parallel port adapter, LinuxCNC finds the port and works perfectly, 50000 base period might cause latency warnings, did not test tuning of any kind.
-PC has only USB2.0, so an addon USB3.0 card should be the first thing to get
-PC has 2 of full X16 PCI-E slots, so perfect for "Home Lab" cramming in two graphic cards for media server, or NAS with a fast SAS controller although not much space for 3.5" HDD drives it might be possible to cram 16 of 2.5" SSD just in the DVD-ROM space
-has enough power supply to run all of the above at the same time
-does about 54 points in Blender Benchmark (pitiful as my R7 7700 does 322 points with temperature limited to 75 degrees C in BIOS !!!)
-Replacing CPU's might just be a good idea as they should be pretty cheap, like 10-20$ probably even less on aliexpress, have not checked, Xeon 5570 are 3.3GHz parts while the included Xeon 5530 are 2.4GHz parts, that is nearly 8 GHZ of difference in total, worth the money if i could find them here for one or two of them, so 2 or 4 CPU's ...
- ... i am out, it is 2:53AM here, need sleep...