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Black Diesel

macrumors 6502
Original poster
Mar 15, 2011
261
113
I have a really good wifi network (ubiquity with WAPs) and I'm getting speeds of 117mb down with 10mb up. I plugged a CAT6 cable in and shut off wifi and my speed goes down to 85-90mb down....is there a 100mb limit with the iMac card? I tried the same thing in my macbook pro and got the same results. I always thought the wired connection was supposed to be faster than wifi? Is there a bottleneck with the iMac and Macbook ethernet devices?

Mid 2011 27" iMac 3.4ghz i7
Mid 2012 13" MBP with 2.9Ghz i7

I thought it might be cable loss from the long run of CAT6 but I'm sitting next to the WAP that has the same long CAT6 length, so why would my wifi be faster?

Regardless, isn't 90mb down and 10mb up sufficient for 4k tv?
 
Gigabit ethernet tops out at 125 MBps (1,000,000,000/8) theoretical. WiFi speeds now can easily exceed that. For example I just ran a wireless test on an A/C network and I saw up to 152 MB/s.

As for what you need, that depends on your source.

Netflix recommends 25 Mbps:

https://help.netflix.com/en/node/306

Youtube for uploads (not sure what their delivery rate is):

35-45 Mbps for standard frame rates
53-63 Mbps for high frame rates

https://support.google.com/youtube/answer/1722171?hl=en

Vudu recommends 11000 kbps or 11 mbps

http://speedtest.vudu.com

The Blu-Ray UHD spec goes up to 128 Mbps (theoretical). Maybe somebody else can say what a typical UHD disk bitrate is.
 
You should be able to do better. My 2011 iMac on a 1 Gb/sec fiber system routinely runs over 800 Mbps both down and up. This is through a 20 ft CAT6 cable from a port on an AirPort Extreme router. Perhaps you have some sort of router limitation?
 
You should be able to do better. My 2011 iMac on a 1 Gb/sec fiber system routinely runs over 800 Mbps both down and up.

I suspect that the OP was quoting MBps not Mbps, ie bytes not bits. You're getting 800 megabit on a 1 gigabit connection, which is about right. If OP is actually getting 100 megabit (not megabyte) or thereabouts then his hardware is likely broken somewhere along the line.
 
I was interested in seeing what a UHD Blu-Ray data rate was. Found this:

"Most UltraHD Blu-ray movies are encoded with a 24-Hz frame rate, 10-bit color, and 4:2:0 color subsampling, a combination that requires only 10.2 Gbps"

"HDMI 2.0a, the connectivity standard used on new UHDTVs and AV receivers, supports up to 18-Gbps signal bandwidth."

"Certain players, however, provide upsampling features to boost color bit depth and increase the color subsampling. When those factors are combined with a 60-Hz frame rate, the player’s output can easily push the limits of HDMI 2.0a’s full bandwidth." [of 18-Gbps]

From SoundandVision.com:

http://www.soundandvision.com/content/do-i-need-new-hdmi-cables-my-new-oled-tv
 
Wifi is a shared medium where everything can interfere. Ethernet works well in ptp communication and is more reliable. All my devices are wired, except my phones. Playstation, Apple TV, MacBook, NAS. Even my smart tv, although i do not use the "smart" features.
 
My concern with your Ethernet setup is:

1. Is the cable bent tightly in any places?
2. Are you running the cable past anything that might block the signal in the cable (florescent lights, microwaves, etc.)
 
I was interested in seeing what a UHD Blu-Ray data rate was. Found this:

"Most UltraHD Blu-ray movies are encoded with a 24-Hz frame rate, 10-bit color, and 4:2:0 color subsampling, a combination that requires only 10.2 Gbps"
That will certainly be for the raw (decoded) video - the compressed video tops out at somewhere around 50 Mb/s*. When you stream it'll be using the compressed data.

*I don't know the actual figure. Traditional 1080p Blu-ray has a maximum data rate of 35 Mb/s and UHD discs offer about 33% more capacity so 50 Mb/s is a guess based on those figures.
 
My iMac gets 930mbs up and down with gigabit fiber to gigabit ethernet. My guess is that your router only provides 100mb/s ethernet.

From your terminal run "ifconfig" You should see something like this:

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=b<RXCSUM,TXCSUM,VLAN_HWTAGGING>
ether d4:9a:20:d0:e6:b7
inet6 fe80::43f:eb75:46d0:6835%en0 prefixlen 64 secured scopeid 0x4
inet 192.168.1.6 netmask 0xffffff00 broadcast 192.168.1.255
nd6 options=201<PERFORMNUD,DAD>
media: autoselect (1000baseT <full-duplex,flow-control>)
status: active
 
Alright guys, I figured out the problem. My ethernet was plugged into a 48 port Netgear switch and the wifi runs through a separate ubiquiti 24 port switch. I plugged my ethernet into the ubiquiti switch and now i'm getting my 117 down and 12 up. So, it must be an issue with the Netgear switch. Is this a higher than average speed? I'm glad to be all "wired" now and getting these speeds. Thanks for the suggestions.

Screen Shot 2017-04-29 at 10.45.18 PM.png
 
Informativ, but not addressing the question.


Gigabit ethernet tops out at 125 MBps (1,000,000,000/8) theoretical. WiFi speeds now can easily exceed that. For example I just ran a wireless test on an A/C network and I saw up to 152 MB/s.

As for what you need, that depends on your source.

Netflix recommends 25 Mbps:

https://help.netflix.com/en/node/306

Youtube for uploads (not sure what their delivery rate is):

35-45 Mbps for standard frame rates
53-63 Mbps for high frame rates

https://support.google.com/youtube/answer/1722171?hl=en

Vudu recommends 11000 kbps or 11 mbps

http://speedtest.vudu.com

The Blu-Ray UHD spec goes up to 128 Mbps (theoretical). Maybe somebody else can say what a typical UHD disk bitrate is.
 
Alright guys, I figured out the problem. My ethernet was plugged into a 48 port Netgear switch and the wifi runs through a separate ubiquiti 24 port switch. I plugged my ethernet into the ubiquiti switch and now i'm getting my 117 down and 12 up. So, it must be an issue with the Netgear switch. Is this a higher than average speed? I'm glad to be all "wired" now and getting these speeds. Thanks for the suggestions.

View attachment 697954
What is the model number of the Netgear switch and how heavily utilized is it? My guess is it is either a 100mbs switch or there is a lot of other traffic from the other devices on the switch causing congestion. If there is only a single uplink port, that could be 48 devices essentially sharing a single ethernet connection.
 
Gigabit ethernet tops out at 125 MBps (1,000,000,000/8) theoretical. WiFi speeds now can easily exceed that...
I'm surprised no one caught this. It is wrong. The OP has 2011–2012 iMacs that support 802.11n. Gigabit ethernet is faster by many times.

802.11ac was introduced with the 2013 iMac. That can be 1.5x the speed of gigabit ethernet under ideal conditions.
 
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