My Macs Are Slower Than My PC Off Cable Modem

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Eric85

Registered
I've posted this message in the tech support area but thought I would also post it in the forum to see if anyone has any ideas. So far, the tech support guys have been great but haven't found the solution.

I have a home office with 3 computers connected to the internet via Earthlink's 5mbps cable modem service through the Time Warner network. The cable modem is a new generation Motorola Surfboard 5101. My 3 computers are:

PowerBook G4 connected via Airport
IBM ThinkPad T43 connected via Airport
Bondi Blue iMac G3 connected via Ethernet

I have any Airport Extreme base station connected to the cable modem and a DLink switch off that to connect the printers and iMac via Ethernet.

The problem I've noticed is that both Macs are significantly slower than the PC on the network. For example, I can download a file off my ISP's local server at about 620 KB/s using the PC but only 260 KB/s using either Mac. Off the Internet, I can go to a site like Speakeasy and get results around 4,500 kbps from the PC but barely hit 1,700 with the Macs.

I've tried directly connecting all three computers to the cable modem and the results are the same. This indicates to me that the Airport network isn't slowing things up. I've also tried numerous things on my Macs to clear up the problem. I've deleted caches, rebuilt adapters, installed and uninstalled Apple's Broadband Tuner, installed other broadband setting scripts, used Cocktail, etc all without any noticeable difference.

My iMac is running Panther while my PowerBook is running Tiger. This seems to rule out something unique to a version of the OS. So with Airport and the OS version ruled out, I'm really stumped as to what could be the problem.

As an example of how this is affecting performance, I can download a large movie trailer through iTunes on my PC and watch it straight through without any delays. The connection can keep ahead of my viewing. On the Macs, I sometimes have to wait 5 minutes before the same trailer is downloaded and can be watched.

I'm out of ideas and would really appreciate any help anyone can offer. Please let me know if additional details are needed.
 
HorqDog said:
Try this, it's from the Apple Support site..

http://www.apple.com/support/downloads/broadbandtuner10.html

I have not reviewed it yet, so your information is appreciated.
Click to expand...

Thanks for the tip. I have tried Broadband Tuner as well as a number of other networking tweaks but none of them have helped. Since I'm receiving about half the speed on my Macs as I am on my PC, I think this is more than a simple problem with tweaks. For some reason, I'm not getting the same speeds on my Macs through the cable modem. Maybe it's a defective modem but that still seems strange considering it's working fine with the Windows PC. It seems to me that something in the modem or on the network is not compatible with my Macs although I have no idea how to prove it other than the speed itself.
 
One more test would be to go to
internetfrog.com
run the speed test on both OS's, looking at the quality of service, Round trip time speeds up/down..

Then start calling your Cable ISP!
 
HorqDog said:
One more test would be to go to
internetfrog.com
run the speed test on both OS's, looking at the quality of service, Round trip time speeds up/down..

Then start calling your Cable ISP!
Click to expand...

I went to the site you mentioned and did a test but I'm not sure the results make sense to me. While I liked the presentation of the internetfrog site, it seemed like it was downloading a fairly small file and from past tests, I've found that small files show good results but large files show the average speed really slowing down. Here are the results I got from two laptops (a PowerBook G4 and an IBM ThinkPad T43) sitting side by side accessing the network through an Airport connection:

Mac:
download 4.92 Mbps
upload 333 kbps
OOS 63%
RTT 38 ms
Max Pause 251 ms

PC
download 2.87 Mbps
upload 360 kbps
OSS 82%
RTT 39 ms
Max Pause 63 ms

Running it a few more times and the Mac speed numbers jump a little while the OSS increases to the 70's and Max Pause drops to 40-60. In other words, running this test a few times on both machines yields faster download speeds on the Mac, higher QOS on the PC by about 20%, equal RTT and Max Pause.

Now, running the speed test of a larger file like the one at www.speakeasy.net/speedtest yields much different results.

Mac
download 1.46 Mbps
upload 346 kbps

PC
download 3.56 Mbps
upload 361 kbps

The thing I like about the speakeasy test is I can try it over several servers. I've also tried direct file downloads off my ISP's local servers and the speed is very much in line with the Speakeasy test. For some reason, the results are opposite from the Internetfrog site and I'm not sure they're believable for download speeds because they are contrary to every other site I use.

What do you make of the results?
 
Well I have to admit the results you achieved are not what I had extected!

Other than the Quality of Service and network cache settings , I cannot understand what the problem is - I have seen this (years ago) on a LAN with WinGate running on a Win NT server, so we went to a Linux server and had equal speed on all platforms...

...I take it your ISP is of no help?

Sorry, I just thought I would say what I know, but do let me know if you do get the issue resolved, I would be interested to hear what happens now.
 
HorqDog said:
Well I have to admit the results you achieved are not what I had extected!

Other than the Quality of Service and network cache settings , I cannot understand what the problem is - I have seen this (years ago) on a LAN with WinGate running on a Win NT server, so we went to a Linux server and had equal speed on all platforms...

...I take it your ISP is of no help?

Sorry, I just thought I would say what I know, but do let me know if you do get the issue resolved, I would be interested to hear what happens now.
Click to expand...

I'm really stumped to say the least and no, my ISP hasn't been of any help. This whole thing started about the time my home got hit by lightening. It fried my cable modem, Airport base station, switch, Ethernet cables, spliter, line filters, etc. The lightening may have even entered the house through the cable line since everything in its path was toast. I replaced the equipment but noticed that speeds weren't very good. To be honest, I don't measure speeds often so it might just be coinsidence that I noticed it about the same time as the ligthening strike, I'm just not sure.

After replacing the hardware, the cable company came and replaced spliters, filters and even the cable to the house. They also upgraded my newly replaced modem with one that was brand new to their system, the Motorola 5101. Prior to that, even the speeds on the Windows machine were slow. With the new Motorola modem, the speeds seemed to improve on some of the speed test sites. What's odd is that downloading the file from their local server is still slow on both machines. It comes down at about 260 KB/s. Of all the tests, that should be smoking at over 600.

I still think something is wrong although they refuse to acknowledge it. I believe it's either the modem or something further upstream that may have been damaged by the lightening. All they do is show up, test the signal levels, do one or two speed tests and claim everything is fine. And it's true, I can run a couple of speed tests that produce decent results, especially the small file tests. But the fact that the Macs are downloading slow and the local file test is still bad tells me something is still wrong. Why I can get faster speeds downloading something off the net versus something on their local servers is a bit of mystery.

Tomorrow, I'm going to my brother's house who uses my same ISP. He's getting almost 5,000 kbps on his new iMac. I'm taking my computer over there and will test it on his connection. If I get the same results, then I've proven it's not my machine. I might then bring his modem to my house and plug it into my wire. If the results drop back down, then I think I will have finally proven it's something upstream.
 
Hey Eric,
What browser/ftp clients are you using when you are doing these tests?
I recommend you try this-

http://mirror.mcs.anl.gov/pub/ubuntu-iso/5.10/ubuntu-5.10-live-powerpc.iso

This is a link to the Unbuntu Live Linux CD for your Mac.
http://www.unbuntu.org

When you download it, see how fast the connection is. I would try downloading it with a few browsers, maybe try Safari, Camino, and even Firefox. See if you are getting consistent results.

Then, burn the ISO file, and reboot the Mac with the disc in the drive. I don't think they have the airport drivers working just yet in this distro (they didnt work on my iBook G4) but you can just plug into the router to do the test.
Use the browser in Unbuntu to also conduct some speed tests. You don't have to worry about messing up your MAC, it runs EVERYTHING from the CD, and doesn't install anything onto your mac.
This way you are eliminating OS X as a culprit as well.
In addition, have you tried just doing some downloading via FTP (instead of via http:) and see if that speeds things up (it should).

Let me know what kind of results you end up with.
 
It's http://www.ubuntu.com

and you need to click on Downloads (on the righthand side of the screen),
then choose a mirror,
and then the ones you can run off of CD are called 'Live CDs', and that is the one to download. FOr the Mac, its a PPC version.
 
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