回複：basic idea

yes add RAM is the basic way. but beyond 4GB seems little use; ATA disk is faster, or one of large cache.
Internet speed depends on many things: 1st is server- some servers that provide contents are slow; connection speed- cable modem is LAN and can be very slow when all neighbors are on line, DSL depends on your phone line quality == you can't help much but changer service; some contents uses lots graphics also slow down.
For wireless, signal strength can be various mainly due to blocking. if too weak try to increase its strength - for DSL modem I only recommend 2wire 2710, its default is 4 and you can set to 10. For cable modem, service provider keep to update s/w and if you use your own modem it may be slower from time to time.
And, if you are always on line, some service provider will limit your BW.