I am a newbie in the space, but let me tell you something: in 2011 I mined bitcoin for two or three days with a dual core CPU just for fun. I got 0.1BTC that I forgot to backup. At the time, It was not profitable due to electricity costs. I learned the hard way that it's worth to mine for future profits.
For low powered CPU's my best bet goes for newly created coins that are easy to mine.
Are they profitable? No, but they are easy to mine. As time passes, higher the difficulty it time it will get too hard to mine. Hold those coins and find a new coin. If one of thoe coins thrives, it will probably get added on a exchange, and will get you profit.
You will also learn about different kind of coins, mining software and pools, blocks, etc, etc. That kind of experience can make you profit in the future: you'll know what to mine and what to buy for best results.
Upgraded my GPU two weeks ago, on a dekstop computer I did not used for the last 3 years. I know have a RX580 mining Zclassic.
I get 0.02ZCL/day and they are not for sale - soon i'll get 1:1 BTCP when Zclassic+Bitcoin Core get forked into Bitcoin Private (BTC owners also get 1:1)
Looked if there was anything worth to mine with my Core2Duo E7400 from 2008. Started mining Dagger this sunday - .main net started January 5th 2018 - not a blockchain, but Directed acyclic graph (DAG). Just like IOTA or Railblocks, but those are already pre-mined.
got a few hundred coins in the first hours and now is getting hard for my low powered CPU, but why not? I also want to see this project from the start. I'm sure I'll learn a lot.
I'll make my profits later.
For your cpu you will need to mine the cryptonight algorithm. To be honest though I don't think your processor will work. Cryptonight requires 2 MB of cache per thread and your cpu only has 3 MB. This will only allow for 1 thread to run at a time and you are looking at maybe making 5 cents a day. You are almost certain to pay more than that in electricity. You could get something like this for $25 which would actually probably give you decent cryptonight performance and fit into your motherboard:
https://www.ebay.com/itm/Intel-Xeon-X5460-3-16GHz-12M-1333-LGA775-Quad-Core-CPU-better-than-QX9650/282594396138?epid=74093793&hash=item41cbf047ea:g:lTAAAOSwhvFZBI1DThanks for the sugestion, i might upgrade de CPU, but i'll rather invest in more GPU's and riser cards.
I'm mining XDAG with weak CPU, but i think this coin get's noticed someone will make a GPU miner.
First minable DAG coin, full node, anonymous skilled dev that did not copy anyone. One week old, over 5 dedicated pools, already strong comunity with over 200 users on discord. Get on board
https://bitcointalk.org/index.php?topic=2552368.1480