Ethernet speeds unusually low on downstream, but not upstream

theLemur

macrumors regular
Original poster
Jan 6, 2008
188
12
At first I thought something was wrong with AT&T Fiber, I was getting 650 down and 950 up. I had the same service at my previous home and got 950 down and 950 up, so I felt the computer (late 2013 retina MBP) couldn't be the issue. I recently switched to google fiber and I still get the 650 down and 950 up, and we tested another computer on the network which got 950 down and up. So now I'm left to assume there is a hardware or software problem with the MBP.

Any ideas? I'd prefer to do a total reinstall, but that's my last resort..
 

Gav2k

macrumors G3
Jul 24, 2009
9,218
1,584
Have you tried the basics like changing the Ethernet cable and cleaning the port?
 

theLemur

macrumors regular
Original poster
Jan 6, 2008
188
12
Have you tried the basics like changing the Ethernet cable and cleaning the port?
I did, but we were able to get the full speeds with the same cable. The only thing different in the equation is the computer (my MBP) and the thunderbolt dongle
 

rockstarjoe

macrumors 6502a
Jun 2, 2006
850
54
washington dc
So I just got FIOS gigabyte service installed, and I am having a similar issue with low download speeds on my MBP (2010 model). I can only get around 200 down and 350 up over Ethernet, which is terrible considering what it should be. I wonder if there is some hardware limitation?
 

jerryk

macrumors 601
Nov 3, 2011
4,860
2,405
SF Bay Area
So I just got FIOS gigabyte service installed, and I am having a similar issue with low download speeds on my MBP (2010 model). I can only get around 200 down and 350 up over Ethernet, which is terrible considering what it should be. I wonder if there is some hardware limitation?
I wish I could get those speeds, especially the upload! Stupid Xfinity cable. 200 Mbps down, 11 Mbps up.
 
Last edited:

robvas

macrumors 68030
Mar 29, 2009
2,801
372
USA
My question would be what are you using to test the speeds? There are so many variables brought into play especially when downloading from the internet.

Have you tried the basics like changing the Ethernet cable and cleaning the port?
It would be highly unlikely that this would affect uploads and not downloads. Theoretically it's possible but I've never seen it in the field.

My other question would be, is this issue even affecting you?
 

Lightsaber

macrumors member
Jan 10, 2015
60
76
Google "OS/X MTU networksetup". You probably need to change the network packet mtu size.
 

Lightsaber

macrumors member
Jan 10, 2015
60
76
This is one of those play with the setting until you are happy with it type of things. Make sure you are setting using sudo/root privileges to make it stick