It very much depends on your workload, particularly with NFSv3 and earlier. We were able to reliably handle multiple gigabit streams no later than 2005 but that was writing to huge files (backing up a ~2-3Gbps data acquisition system being processed by 4 Mac or Linux clients).
Small files were much worse because they require a server round-trip every time something calls stat() unless you know that all of the software in use reliably uses Maildir-style practices to avoid contention. That meant that e.g. /var/mail could be mounted with the various attribute-cache values (see acregmin / acdirmin in http://linux.die.net/man/5/nfs) but general purpose volumes had to be safe and slow.
If you read through the somewhat ponderous NFSv4 docs, there are a number of design decisions which are clearly aimed at making that use-case less painful. I haven't done benchmarks in years but I'd assume it's improved significantly.
Small files were much worse because they require a server round-trip every time something calls stat() unless you know that all of the software in use reliably uses Maildir-style practices to avoid contention. That meant that e.g. /var/mail could be mounted with the various attribute-cache values (see acregmin / acdirmin in http://linux.die.net/man/5/nfs) but general purpose volumes had to be safe and slow.
If you read through the somewhat ponderous NFSv4 docs, there are a number of design decisions which are clearly aimed at making that use-case less painful. I haven't done benchmarks in years but I'd assume it's improved significantly.