General :: Control Gzip Compression Rates While Archiving Files With Tar?

I have a script which periodically backs up a directory using the command "tar -czvf [name] [directory]" but my problem is that the script has recently been putting a lot of stress on the server (Minecraft SMP) and tends to lag players as it backs up, which recently has been taking nearly 5 minutes.So I need to know if there's a way to control the GZip compression rate at the same time that it archives and backs up the files?I understand that I can first tar the files and then GZip them separately with a different compression rate afterwards, but this would not work because it names the files with the current server time, which sometimes changes in between commands.