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Broadband Tweaking

E

Ellen

macrumors 6502
Original poster
Nov 3, 2007
299
34
I am a new Mac owner, so forgive my Windows orientation (!!!) but is it possible/desirable to tweak OSX to improve broadband performance and, if so, how does one do that? I am running my new iMac via the wireless connection, but even assuming that would slow things down a bit, my speed has dropped from 9000+ to barely 2000. On my former computer (Dell) I used a program to modify the RWIN and tweak my connection, but didn't know what is normal/recommended now. Thanks.
 
I have run various speedtests, including nyc.speakeasy.net. The difference between my Dell and iMac is significant, and I've not changed my router or cable modem - though the Dell was wired to the router and right now the iMac is using the wireless connection. I know that the wireless security is probably degrading the speed a bit, but would not have expected that much of a hit.

I also ran the Tweak Test at www.broadbandreports.com - which said my RWIN was out of range - but I know that site is geared towards Windows tweaking (there is a Windows utility there that I used in the past to tweak my connection, but no Mac instructions and little OS X information).
 
Ellen said:
I have run various speedtests, including nyc.speakeasy.net. The difference between my Dell and iMac is significant, and I've not changed my router or cable modem - though the Dell was wired to the router and right now the iMac is using the wireless connection. I know that the wireless security is probably degrading the speed a bit, but would not have expected that much of a hit.
Click to expand...

That may well be part of the issue. Try connecting the iMac directly to the router and see what happens…
 
what are the specs on your imac, hardware and software? that might help some. i seem to remember there being a problem with this several months back and i don't remember what people were doing to resolve the problem. if it's an older mac, i'd do a search here and on the apple forums and see what you can find.
 
It's a new Aluminum iMac - 20", 2.4ghz. I bought it about a week ago, set it up over the weekend and installed Leopard via the dropin disc.
 
awesome! nice pickup. then disregard what i said earlier, cuz i haven't seen any of those problems in a long while. i'd recommend comparing apples to apples (pardon the pun) and test both out wired and wireless and see what difference you have. iirc, one of the improvements in leopard was it's broadband tweaks, so there shouldn't be much for you to do.

maybe someone more knowledgeable than will come by with better advice. :)
 
10.5 automatically optimizes for broadband connections based on usage.

Do not compare wireless to wired (duh). If your iMac is still significantly slower on a wired connection, make sure your ethernet is in full-duplex mode (sometimes autodetection fails and gets this wrong).
 
Thanks, I will definitely try a wired connection and check the router.

When you say that 10.5.1 optimizes based on usage, do you mean that the more I use the Internet connection, the settings may change?
 
Ellen said:
Thanks, I will definitely try a wired connection and check the router.

When you say that 10.5.1 optimizes based on usage, do you mean that the more I use the Internet connection, the settings may change?
Click to expand...

The optimizations are dynamic and do not require user intervention.
The same is true with regard to disk defragmentation; OSX handles it dynamically and automatically.
 
Eventually my brain will shift over from Windows, but the more I learn about what I "don't have to do" with OS X, the more I love my iMac!
 
One thing I could recommend is turning off TCP's delayed ack.

Code: 
sudo sysctl -w net.inet.tcp.delayed_ack=0

The combination of broadband modem and TCP delayed ack MAY
cause noticeable performance degradation. I THINK turning off delayed
ack is safe enough to try unless your broadband upload bandwidth is
significantly smaller than that of download bandwidth.

I have not looked in to Leopard's new so called broadband optimization, but
I guess it might do DRS(dynamic right sizing) so you don't need to increase
the receive window size. However, try ping to your favorite sites and if the
RTT is greater than somewhat over 100ms (in U.S.) you might need to try to increase the receive window size.

Someone might be happy in fact that your Mac is doing the broadband optimization without user intervention, but Vista does, Linux does, every recent OS does that. :)
 
Tried wiring the iMac to my router - still getting the same (low) speeds, so it doesn't seem to be the wireless connection that is causing this - at least I can forego a cable.....
 
I've never used Bluetooth before but I have the new wireless keyboard and mouse - is it possible that Bluetooth is interefering with the builtin Airport connection for my iMac, and that is affecting my wireless speed?

When I set up my iMac it configured the wireless automatically - I have not changed the settings it selected.

I have a Linksys router. All the settings are same settings I was using previously, when the router was wired to a Dell PC, except that I found that I needed to change the encryption - I have a Dell laptop, and after the iMac was up and running the laptop was knocked off my network. If encryption is set for WPA Personal on the iMac and WPA-PSK on the laptop they are both able to access the network.
 
I'm sure this doesn't help you out, but I just ran the speed test at dslreports.com on both my dell laptop running xp and my mac running leopard. Both are using a wireless connection to my linksys router. Both had comparable results of about 4700k.
 
I have tried adjusting every setting i can think off - even if I turn off security on the router (and the Airport settings on the iMac) there is no change.

I replaced my coaxial cable right before I got the iMac, as I needed to move the location of the router and cable modem, so I was wondering if that could be the culprit - but my upload speed is nearly at the cap, it is just the download speed that is literally 10-20% of what it was a few, pre-iMac days ago.
 
did you check the full duplex setting as mentioned above? are all your other settings comparable to PC? is your firewall on? other programs running that are using bandwidth?

honestly, it sounds like you have the same problems i was seeing on the boards a few months ago. i thought they'd been worked out.
 
Firewall is not on, and settings are same as before except security setting on router is now WPA Personal, and turning off security does not affect speed. Is not full duplex the setting for a wired ethernet connection? I'm used a wireless connection?

I have Gmail Notifier running but that's the only 'always on' program using the internet connection.
 
I wound up buying a new router and so far things are much improved - a Netgear RangeMax Wireless-N. Both wired and wireless, the computer is now 9000+ (I have not turned on security yet). The "Geek Squad" guy at Bestbuy told me that my 3 year old Linksys G router was probably the culprit, and to his credit he did not point me towards the most expensive option (though he did say the Apple N router is the best), the one I bought was on sale. So, things are looking up!!!
 
Of course, things are never simple!

If anyone has a Netgear router, I would appreciate knowing if you have experienced this - when I try to change the password to access the router, a box pops up and you type in the old and new passwords. Then I get a box saying to access the router config pages I need to put in my router name and password - when I put in the old one (since the change has not become effective yet) or new one I get a message saying the name and password are wrong. Any thoughts would be appreciated.
 
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