Kewlx25 :
I tried to find 100Mb switches, but they're more expensive than gigabit.
Yeah, that's "10/100" which is slower than Gigabit.
If they are more expensive to boot then that's even more of a no-brainer to get Gigabit.
Remember the SWITCH is only about connecting local devices together for direct transfer or to share the ROUTER connection via the same Ethernet cable. For example, I have a PC, WDMY CLOUD, and Samsung BluRay player attached to a Gigabit switch. One ethernet cable is in the wall down to the basement and into the ROUTER.
Those things on the Switch can talk directly. If I copy a movie from my PC to the WDMYCLOUD it goes from PC, into Switch, then into the WDMYCLOUD. Router is not involved.
Don't overthink this. Get a Gigabit Switch and CAT5e.
(CAT6 cables aren't needed unless you want transfers in excess of about 110MBps (i.e. between computers with high-speed HDD, or SSD).
For CAT6 you're looking at CAT6 cable and 10Gbps for network card, switch, and SSD... most HDD's can only benefit a little or not at all. Every device has to be fast or you're with the weakest link. It's not worth investigating for most people and has nothing to do with your INTERNET speed using the MODEM)
For Gigabit,
Make sure:
a) enough connections
b) Gigabit
c) QUALITY appears good
EXAMPLE:
https://www.amazon.com/TP-LINK-16-Port-Ethernet-Desktop-TL-SF1016D/dp/B003CFATTM/ref=sr_1_1?s=pc&ie=UTF8&qid=1473917499&sr=1-1&keywords=gigabit+switch&refinements=p_n_feature_keywords_two_browse-bin%3A7306163011%2Cp_36%3A1253504011
Other:
In case you are confused, most of this is fully compatible. You can mix fast ethernet cables with slow routers, fast switches, super-slow network cards. Whatever. The PERFORMANCE is determined by what is the weakest link. (even with SLOW cable in between FAST network cards I believe its supposed to DETECT this and send packets at the proper speed to limit packet errors.