Foo - Network speed issue.

My wife and I have AT&T U-Verse 18 Mbps service, and we regularly get speeds ranging from high 15 Mbps to high 18 Mbps. Until recently, that is. I noticed that the connection was sluggish. Usually I'd chalk it up to streaming HD via Netflix or Hulu, but then I started noticing that basic websites would load at extremely slow speeds when I'd be the only one on the network.

I did the usual trouble shooting steps: restarted the U-Verse gateway & the D-Link router, restarted the computer, etc., etc., but nothing fixed the problem. So I called AT&T. They did some basic over the phone trouble shooting (reset the gateway) which didn't fix the problem, and scheduled a tech for the next day.

The tech came out and started doing his trouble shooting. When he'd plug his laptop into the gateway, he'd get great speed. When I connected the MacBook directly to the gateway, I'd get less than 1 Mpbs down. If I connected the iMac or Mac Mini directly, I'd get 17+ Mbps down. If I disconnected the MacBook completely from the network, speeds would be great, even when doing simultaneous speed tests on 3 devices. If it was connected, whether via WiFi or ethernet, all devices on the network would get slow speeds. We thus determined the problem has something to do with the network card on the MacBook.

Since then, I've disconnected the ethernet connection from the MacBook, and only connect via WiFi when I absolutely have to do something on the MacBook. But it's a PITA to have to do that. I'm guessing that the network card is bad, and should probably be replaced. I have an appointment with the Genius Bar at one of the local Apple Stores for Sunday afternoon to have them trouble shoot it, but was hoping someone here could possibly shed some light on what might be the problem, and if there's a simple fix for it.

If it does turn out to be the network card (which is most likely part of the motherboard and therefore expensive to repair), would I be able to pick up a USB WiFi adapter for it instead, and have it connect via that? Or would the MacBook still use its own network system even if it's using a USB adapter?

I'm running OS X 10.6.8. It's fully up to date as of 6/24.

tl:dr - MacBook is slowing entire network speeds when it's connected either via WiFi or Ethernet. Network speeds are great when it's not connected. Speeds for all connected devices are slowed by the MacBook being connected.

Don't laugh, but you could have a bit of malware there. Yeah, I know, you're on a Mac, but even Apple recommends you scan software, etc, before downloading, because even OS-X has some vulnerability to trojans, etc.

are you sure the macbook isn't downloading updates?

Tom - good thought. Checking that now.

AEO - yes, I'm sure it's not. Even after it downloaded the last OS X update the other day it slows the network. Besides, if that were the case, the iMac & Mac Mini would have slowed the network when they downloaded their updates, and they didn't affect the overall network speed.

I use an iMac and installed SOPHOS A-V for Mac (http://download.cnet.com/Sophos-Anti-Virus-for-Mac-Home-Edition/3000-2239_4-75328306.html?tag=mncol;1) about a month ago because I received a suspicious email from the "Apple Security Center (http://reviews.cnet.com/8301-13727_7-20062597-263.html)". I googled that and sure enough it was a ploy. Do the update after downloading as the one CNET has is not the latest. I have version 7.3.0C.

snoop, wireshark, netstat

Something is amiss, and I'd suspect software before hardware.

Virus scan came up clean.

Apple store couldn't replicate the problem, but did give me tips on how to narrow it down using Target Mode to book from another Mac (and sold me a $30 FireWire cable to do it, but told me I could return it if I didn't need it after I was done with it). If the problem still persists when booting from the other Mac in Target Mode, then it's a hardware problem. They also confirmed for me that if it is the network card, getting a USB WiFi network adapter will work just fine, as long as it's Mac compatible and I follow the setup instructions. They also informed me that the network card is an actual card, not part of the motherboard, so it's replaceable.

Maybe you offended it. Did you spill anything on the keyboard lately? I too would suspect software, if it were hardware, just the wireless would be slow or just the wired NIC. Maybe try reinstalling the browser? Im no MAC guru but I know you can reinstall the TCP/IP protocol stack in windows, maybe you need to do stuff like that. Usually takes a few minutes but worth the ability to rule out those possibilities.

As I mentioned previously, the Genius at the Apple Store suggested booting it via Target Mode from another Mac to see if the problem persists in order to rule out hardware issues. I just did that, and the problem didn't appear at all. Another suggestion they made was to create another user account on the MacBook and check if the problem persists then. I also did that this morning, and the problem didn't appear. As soon as I went back to the main profile, internet speeds went down to below 1 Mbps. I also tried speed tests using different browsers (Firefox, Chrome, Safari), they all were slow.

So the problem is with the main profile. I'm about to head to the Apple store to return the Firewire cable and see if they have any other ideas. I may just wait for Lion to be released (Release the Lion!) and see if the upgrade will fix it.

Any other thoughts?

As I mentioned previously, the Genius at the Apple Store suggested
...


Was I the only one who took this as sarcasm? Apparently, they really are called 'Geniuses'. :twitchy:




Any other thoughts?

This:


Don't laugh, but you could have a bit of malware there. Yeah, I know, you're on a Mac, but even Apple recommends you scan software, etc, before downloading, because even OS-X has some vulnerability to trojans, etc.

The emphasis was mine.

A friend suggested I check the Login Items in the Preferences Pane of my user account. He had a similar problem that was caused by a specific item that was trying to access a drive that didn't exist and it ate up CPU cycles. So I checked mine. I had a $#!+load of items in the Login Items pane.

The Genius Bar guy recommended a rather radical fix, and I went with it. Rather than go through all the items in the Login Items pane, turning them off one by one & rebooting, he backed up my Library folder and then deleted the original, forcing the system to build a new one. Of course, that meant all my preferences were nuked, but I didn't lose any software or data. So far so good on the network end. I now just have to set up the MacBook to my liking.