Open Network Utility in Applications>Utilities>Info tab, select Ethernet & what is the Link Speed & are there any Errors/Collisions on the right?
Open Network Utility in Applications>Utilities>Info tab, select Airport/Wifi & what is the Link Speed & are there any Errors/Collisions on the right?
The iMac and MacBook were speed tested independently, not simultaneously also a Fibreop technician teted his pc laptop. The MacBook and the pc tested at 50 Mbps the iMac only 35 Mbps . Thanks for the replies
One way to test is to Safe Boot from the HD, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, Test for problem in Safe Mode...
PS. Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive
Reboot, test again.
If it only does it in Regular Boot, then it could be some hardware problem like Video card, (Quartz is turned off in Safe Mode), or Airport, or some USB or Firewire device, or 3rd party add-on, Check System Preferences>Accounts>Login Items window to see if it or something relevant is listed.
Check the System Preferences>Other Row, for 3rd party Pref Panes.
And in your instance it might possibly be Spotlight or Time Machine messing with you...
Open Activity Monitor, Show:>All Processes, sort on CPU%, see if anything using too much CPU% when this happens, click on Memory tab, do you have many Pageouts?
Open Console in Utilities & see if there are any clues or repeating messages when this happens.
Is Printer sharing or iTunes or iPhoto sharing turned on in the iMac? If it is trying to enable Rendezvous without other devices that can still eat up bandwidth. Turning off sharing on all applications that can share unless absolutely needed can help speed things along.
Thanks everyone for all your suggestions, I attempted them all with the exception of the safe boot, I'm a bit out of my depth there. Still only getting downloads of 35 Kbps when I should have 50 Kbps, oh well, 35 ain't bad.