B3n3d1kt:

You have to decide if you want/need the system available 24/7. If yes, then there is no other way than a new certified system.

You can also get 24/7 availability from redundancy. More expensive but arguably better.
if your raid controller goes ***-up, HP support will not get your data back.
But yes, you have to know your machines well to be your own support.

B3n3d1kt:

1. Refurbished certified system. Price might look good, but check for waranty because components normally fail early or after a few years.

Is not my experience with server grade gear, only with consumer grade and machanical harddrives.
My Supermicro machines will outlive a turtle, I'll admit my experience with HP is more limited.
With an HP workstation 2015 or younger I personally wouldn't worry, clean out dust, check the fans.

B3n3d1kt, if you have a large sample size, I'd be very interseted in failure types and numbers.
Other than that, we have around 100 HP machines at my university, I can try ask there.

Thanks for all the comments folks! Honestly i feel even more lost now. The HP Workstations never seen enough. Low RAM, too small HDD not SSD, no thunderbolt 3. I feel like building one is the only way forward and then buying an over priced Video card? I wish apple was still an option lol

the dual processor HP ones are okay.
Dual 8 core will last you 10 years.
Low RAM is swiftly upgraded, SSDs installed,
If you have enough PCIe slots, you can't loose.

Thunderbolt is overrated imho, is just 4 lanes of PCIe on an external cable.
USB 4 will kick Thunderbolt 3 in the butt some day, you can upgrade to that, the iMac can't.

The lost-ness works both ways. I saw a 6000$ HP Z840 the other day for 1700$.
Do I need one? Ablolutely not. Was I tempted to buy one? Absolutely yes!

The only thing better than a HP workstation is knowing computers very well and going DIY.

And yeah, GPUs are a problem. For now, whatever you find in your attic might have to do.

I know i'm being told I can't do AMD if I want Thunderbolt 3 so i get the limitations but I need a fast import and allot of drives I am given are t3 so it's pretty essential.

Okay what about this? I guess there arn't any PCIe Lanes to use in future. I'll buy Corsair Vengeance LPX 32 GB for RAM and apply them? Do i need the Xeon Broadwell? Thanks you help folks. Getting there!?

Okay this is better - I guess if i can find one of these second hand but I tempted to go for this as it seems to have everything i need

I'm using NAS with 10G... I am not using Thunderbolt. Thunderbolt is not needed! A lot of motherboards like the one I mentioned earlier have 10G built in. Its fast enough for Avid editing and playing back RAW in Resolve.

They're both a bit meh

we want something with 2x Intel Xeon E5-2667 v4

like this:

https://www.uli-ludwig.de/HP-Z840-Workstation-2-x-8-Core-Intel-Xeon-E5-2667-v4-320GHz-128GB-RAM-512GB-SSD-nVidia-Quadro-M6000-24GB-Win-10-Pro_1#tab-description

And hard pass on the corsair ram.
First you get your computer, check the type of ram it uses and buy the exact same.

Looks good! I can't see the price, how much is it?

2880€ -> 3440$

and that's including 20% vat. OP probably doesn't have to pay.

and whoever doesn't want to spend their summer holiday in Wuppertal, Germany (insanely boring),
can send it to me and pick up in Vienna (also boring, but less culinary cruelty)

my price: side of pork for teh cat.

Hp Z840 forget the SSD get the HP turbo card (quad)

Stick in a 512gb boot NVMe and a 1TB media NVMe.

I'm seeing 1.5gbs read write speeds.

It's insane. 

20% vat-ouch. That's a good price if it comes with a warranty. You might save some money with the RTX2080 or RTX3080, but it's hard to say without knowing what thier charging for the card. At this point that's a good card with that much ram and cud's cores (which resolve likes). Go for it!

Does the older HP Z840 work with NVme? I thought they wouldn't. I think the M6000 is 2 slots wide. I have BMD 12G card and not sure if I have an extra PCI slot. Do they still make SATA NVme? But yeah crazy technology.

Fazz Powell:

Does the older HP Z840 work with NVme? I thought they wouldn't. I think the M6000 is 2 slots wide. I have BMD 12G card and not sure if I have an extra PCI slot. Do they still make SATA NVme? But yeah crazy technology.

The HP Z840 does support NVMe via the turbo card. Mines got it and works well. 

Good to know, so 4x512GB drives are in the HP Turbo Quad? You don't need this card as an interface and then add a NVMe drive-right? I was confused by your comment and I don't know squat about these-obviously.