TCP/IP was designed to operate over wide area networks as well a smaller ones. On large networks, you may from time to time encounter long delays. This is a normal (often annoying) condition and the IP protocols are ready to cope with this. A bad DNS or broken network connection making the DNS unreachable will cause all kinds of delays (several seconds). Fortunately, quite often a backup facility exists (i.e. a second DNS) and after some timeout, the system becomes active.
Unfortunately, this often hides the real problem and slow speed is ttributed to the wrong reason. It may be attributed to an overloaded Internet, or to an ISP over-selling bandwidth.