UFBC

Very valid point. I have an i5-4460 that has a higher TDP of 84w in a GA-H97 board and 3*4TB in a badly laid out case but when it does a parity check only consumes 50w of power for the complete system. Drives/CPU/mainboard and cooler. Not sure how it would perform for a VM though.

Oh and in the Xeon range processors ending in L are usually the low power models but often they are only supplied to server manufacturers exclusively for datacentres, but they often come up on ebay after they have done 2-3 years service and replaced by a newer server.

If you want to find low power CPU specs a good place to go is https://www.cpubenchmark.net/CPU_mega_page.html There you can type for example i5 in the search, then narrow down by socket type of motherboard and TDP (power usage) of the CPU Typically the processors ending with S or T are low power and no letter or K are high power when it comes to Core i5/7 processors An S processor might be better then a T as they have higher clock rate for single thread tasks.

I Second the XEON route as the way to go if you are trying to save money and reduce power consumption. All the data centres use them because they are low power and great for virtualisation. If I were trying to save money I would get a refurbished workstation or tower server from an IT recycling company that wipes ex-lease business systems. Then you have a 24/7 grade device likely to have IPMI and VM support. Plenty of drive space and often a headerless USB port internal on the board. One system I did was based on a Dell 7810 ex-lease with Dual E5-2600. There are smaller models that are single socket also. The one disadvantage of workstations over tower servers is there is not so many drive mounting positions if you are going 3.5" drives. Also the tower servers often come with an LSI card for increased drive support.

Thanks for the suggestions. You got me thinking... Yes the case side is flat metal on HDD side with some holes but it slides on so thermal transfer from drives to case may be tricky. This said I had a spare case the same that has the mesh on CPU side and I have swapped this with the flat panel so now plenty of fresh air from both sides. Old side panel left and replacement on right. I also have a cooler heat sink/fan unit from a low profile GPU that I may mount in the HDD side with a temperature controller inline.

Complete noob to UNRAID (all of 4 days) Thought I would share my first attempt and building a TINI UNRAID box for my home. It is in an Inwin BQ656 mini ITX case measuring just 225 x 87 x 281 mm or 3.3 litres 12Tb raw 8Tb protected 3*4Tb Seagate ST4000LM024 2.5" drives 2*120Gb SSD 2.5" drives for cache pool in raid1 for redundant cache Gigabyte Technology Co., Ltd. H97N-WIFI Intel® Core™ i5-4460 CPU @ 3.20GHz 8 GiB DDR3 Dual 1GigE and 2*2 mimi 11AC WiFi I know people will cringe at my drive installation with minimal cooling but the objective was compact over everything else. Only using it for backup of home PCs/laptops and drives sit at 35c most times and spun down more often than active. System consumes <50 watts of power most of the time.