Take a look locally though, I'd expect to find something cheaper than that you can collect.
I'd hope to spend no more than a tenner.... maybe 15 quid at a stretch for some basic green or blue PCB stuff.
As an aside, on the CPU front.... some user suggested a Q9650 (Core2Quad, 3GHz) is compatible... only the 95W variant though... Not the QX9650 which is 130W.
https://www.dell.com/community/Optiplex-Desktops/Optiplex-380-CPU-upgrade/td-p/7188055
However, I can;t find any way to validate that. Dell's support site for older stuff is pretty poor.
I have found a CPU-Z validation of a Q6600 working though
https://valid.x86.fr/k9pmtq
Which can be had for a fiver, from Korea:
https://www.ebay.co.uk/itm/Intel-Core-2-Quad-Core-CPU-Q6600-2-4GHz-8M-1066-LGA775-SLACR/183118728120?epid=74103280&hash=item2aa2ba0bb8:g:fMcAAOSwZlZaTLPE
Interestingly, that validation has a 2x2GB config for the RAM......
Out of curiosity how can I tell if my board is capped at 2x2gb? I mainly use Aida64 as my go to and that states max 4gb and board only has 2 slots so that'll be the 2x2. Is there any other tools or utilities I can use to check?
Unfortunately, with Dell's site not covering it off anymore - the only way to know with 100% certainty, would be to try.
If everything (Aida/Crucial etc) were consistent, then fair enough... pretty good idea.
But with differing info, who knows.
EDIT
Another couple of validations using the board.
https://valid.x86.fr/j2ksh1
2x2GB
http://valid.x86.fr/tprq48
1x4GB
So... it might be the board will take a 4GB DIMM, but maxes out at 4GB...
Very few people have validated results with CPU-z and that board (that I can find at least), so I wouldn't take either result as gospel.
EDIT 2
Supposedly, this guy "verified" it in their own system - adding another 4GB module to an existing, and it works:
https://www.dell.com/community/Desk.../Maximum-Memory-for-Optiplex-380/td-p/4494846
Take that for what it's worth.
EDIT 3
@Tetsuo1981 - tagging you incase you're not getting notifications for all my edits 😂
So, finally found a link to the manual... linked by a poster here:
https://www.dell.com/community/Desktops-General-Read-Only/Dell-Optiplex-380-max-RAM/td-p/4720466
Direct link:
https://www.techdata.com/business/dell/082010_123/Files/august2010/Dell OptiPlex 380.pdf
Which states:
Memory Options3 2 DIMM slots; Non-ECC dual-channel 1066MHz DDR3 SDRAM, up to 8GB Max system memory