I have one of those 27 inch iMac’s that I bought probably around the end of 2009 or beginning of 2010. In the last year it has developed an issue where the internet on it runs so slow no matter what browser or application I use, half the time it can’t even load the Google homepage. All our other devices including other Apple devices run great.
The computer has barely anything on the hard drive and I don’t think it has any viruses. I have done all the system updates and totally erased all the internet settings and set them up from scratch and this temporarily seemed to speed up the internet but then it slowed down again. It still has the old ass original OS Snowleopard or whatever that came on it. Would updating it to Yosemite help, of course it goes slow I would probably have to have a disk or something. So how do I fix this issue?
It sounds like there is some interference between your wireless router and your iMac. Some quick things to try (you might have tried some of these, but sometimes we forget the obvious)-
Shutdown your iMac, router and modem for 5 minutes, then restart.
Physically move the iMac or the router to a new position. It sounds crazy, but even a foot or 2 really could make a difference.
Plug the iMac directly into your modem. If it works fine when physically plugged in, you know it’s a wifi problem. If it still doesn’t work, then there might be a problem with your iMac.
Change the wifi channel. If you have an Apple Airpot Base Station, you can do this using the Airport Utility app in your Utilities folder. You can also change its frequency from 2.4 GHz to 5 GHz, if the router supports that function.
Hold down the option key while clicking on the wi-fi menu on the right side of your menu bar.
That’ll bring up a few diagnostics in the menu itself, plus a choice to “Open Wireless Diagnostics…”
Select that, then open the “Performance” window from the App’s Windo menu. That’ll give you signal/noise/speed info on your network connection. Look at the info, and move router and or Mac as needed. You may just need to switch to a different wi-fi channel to get better S/N. That’s done thru your router software.
When the Wireless Diagnostics App quits, it’ll leave a nice lttle report on what it found on your Mac’s desktop. That’ll likely give you more info than you’ll ever need. Switching channels and moving or rotating routers/Macs arounds is all I usually ever need to do. Most likely your problem is poor signal to noise.