Hi
Cable quality can have alot to do with speeds. If the connection is still slow, it probably is the network cable, otherwise there is something misconfigured on the desktop or router. But sometimes it can be more important to have a connection than have a high speed connection. For example 10Mbps can be far enough to share an internet connection.
List of Ethernet standards
http://www.webopedia.com/quick_ref/EthernetDesignations.asp
Maximum cable lengh for ethernet depends on what kind of ethernet you are talking about
Gigabit Ethernet (over copper), 1000baseT
Speed: 1000 Mbps
Max Len: 100 Meters
Cable: UTP, RJ-45 connectors
Fast Ethernet, 100baseT
Speed: 100 Mbps
Max Len: 100 Meters
Cable: UTP, RJ-45 connectors
Twisted Pair Ethernet, 10baseT
Speed: 10 Mbps
Max Len: 100 Meters
Cable: UTP, RJ-45 connectors
Thin Ethernet , 10 base 2
Speed: 10 Mbps
Max Len: 185 Meters
Cable: RG-58 type coax, 50 ohm impedance
Thick Ethernet, 10 base 5
Speed: 10 Mbps
Max Len: 500 Meters
Cable: RG-58 type coax, 50 ohm impedance
Ethernet to Fiber media converters are starting to come down in price – they can be found for under $150. When 100Meters is not enough distance, an Ethernet to fiber media converter can be placed on each end making the maximum distance something like 40Km. Another use for fiber is electrical insulation. Some people like to run cables underground between homes. If you run CAT5 cable, the homes have different ‘ground potentials’ and you will burn out network card durring any electrical storm. The solution is fiber! Run fiber betweeen the homes or run a pair of fiber converters on one end of the cable with a short fiber run. This will electrically separate the two homes.
Cable specifications for the 10-Mbps 10BaseT cable with RJ-45 connector:
Category 3 or Category 5 UTP with 22 to 24 AWG
Maximum segment length ….. 100 m (328 ft.) for 10BaseT
Maximum network length ….2,800 m (9,186 ft.) (with four repeaters)
Cable specifications and connection limits for 100-Mbps transmission, RJ-45 connector.
Category 5, UTP, 22 to 24 AWG
Maximum segment length …. 100m (328 ft.) for 100BaseTX
Maximum network length …. 200 m (656 ft.) (with one repeater)