Well really if the server is running that hard then clearly there is a need for an increase in resources. Was this just for that peak or is the server continually running at high usage. If it is the later then the only solution is to increase the resources on the server. As to specific issues with v3.8 then this is an old version and any issues or problems that may have existed been fixed or upgraded in later versions.
Generally every version over the last 10 years works just as intended. It is only at times like you have suggested there can be issues, probably more with the server resources, operating system or SQL Server rather than the solution.
Unless you have some specific error messages from the various logs that can be looked at, then best guess is that you need to more resources on your server, or a way to scale them up when peaks occur.