Will 100 Mbps client slow down 1000 Mbps network?

Newbie question:

We are planning to setup a LAN in our lab, and are looking at gigabit ethernet switches. A couple of our older computers have 100 Mbps ethernet, will they slow down the whole network when all other devices are 1000 Mbps? If so, what can I do to prevent this problem? What specific features should I look for to keep my network speed as fast as possible even with a few "stragglers"?

Thanks.

Solution 1:

No, only the 100/mb clients to the switch will be affected. However, you need Cat5e minimum to run gigabit (Cat6 is certified to run gigabit speeds). So if all your cabling is Cat5, then a gigabit switch won't do you any good.

Solution 2:

No, they wont. Only transfers to/from those clients will be 100mbit