My steadily ageing server is getting to EOL - the power supply is making some interesting noises, so I'm currently powered down whilst I order/fit a new PSU. But since the CPU/MoBo/RAM will also need an upgrade soon I obviously need to think ahead. There's a few things to think about (and get thoughts of from this community):

• Can I get a single Xeon CPU now, fit a dual-CPU board and then add a matching Xeon later? Obviously it'll need to be the same make/model(?) but I'm not convinced I need 16+ cores of goodness. Sure, I WANT 16+ cores of goodness, but this needs to pass a sanity check (not to mention the partner test!! ). I seem to have read various mentions of 'matching pairs of Xeon's' - which makes sense if buying used, but is that a thing for buying new?
• Speaking of used/new - obviously it's cheaper going used. But I'm guessing that you can go too cheap/too used (the craze for E5-2670s makes sense when they are £50-60 each, but they do draw a fair bit of power) and there's a fair number of pitfalls to avoid. Am I over-emphasising the downsides of used?

 

• 750w PSU should be more than enough - right?: Since one option is to just upgrade the PSU now (and do the rest later) I need to slightly guess future config - but I'm going some way to trip online calculators into suggesting an 850w PSU. I'm talking TR1920X, 32GB RAM, 8-10 HDDs, 2x1050s (which is a million miles ahead of my current setup) and I'm still in 750w territory. Or do I cover my bases with an 850w? Does it really matter if the PSU is way over the top for the final build (and a 450w would have beed ample)?

 

There's a lot of other questions - for instance there's a lot around VMs I need to bottom out - I want to essentially deploy small test labs as VMs within Unraid (including pfSense VMs acting as routers). But I'm not convinced if this is just me trying to justify a pair of good Xeon's at this stage! 

Edited April 11, 20188 yr by MrLeek

Yes, but there will be limitations on memory and some PCI-e slots might not work without the second CPU.

Thanks for the response Steven.

 

Clearly my Google-fu was failing earlier since I couldn't find any mention of the subject - but my Google-fu is fixed now (adding caffeine fixes many things!) and what I found confirms what you said: https://www.servethehome.com/answered-cpu-dual-processor-motherboard/

 

One thing worth flagging (in case someone else's Google search brings them here); it's possible to put the single CPU into the 'wrong' slot. Some boards will tie the LAN connection through some PCI-E lines into CPU slot 1, but if you've plugged your new CPU into slot 2....then the Ethernet won't work. By all accounts MoBo manuals will document which slot to use first.

 

Anyone know if there's unRaid specific issues with doing this? Probably not, but better to check first...