trying out a new host, I periodically check phpsysinfo, During the day, I see the load go up to 2-4.5. Right now at 9pm, it's 0.5-1.3. Are these good values? Of course these are just snapshots, but fwiw...
0 is always the best, but I really wouldn't like to see anything over 2%, which really means the server struggles at times.
If we're talking about CPU usage in percents, 2% should definitely be no problem. If we're talking about server load (avg number of processes that are waiting for CPU access), then "2" can still have lots of benign explanations and is definitely not a sign of the server struggleing in any way.
While most people and hosts prefer to see server load under 1, I doubt many would truly panic at the sight of a temporary load of 4 as long as server performance is more or less the same.
As far as I've seen, cheaper hosts will accept higher average load on their servers as "normal", but not to the extent to which server performance is noticeably affected.
Up to a load of '1' per processor core basically means 'no waiting'. So if that server has 4 cores, a load up to 4 is absolutely perfect.
However, a webserver usually can handle a higher load. Sure it will slow down a bit, but it would not be noticable for the visitor(s) of the website(s). Personally I try to keep server load under '2' per core. Because then everything will be fast without slowdowns But if needed, up to '4' per core is also still possible. Higher than '4' will noticably slow down the website(s).
In your case that would mean max '4' per core, 4 cores...thus a load of 16 max