Windows 7: Poor upload speed in normal mode, fine in safe mode

My speedtest.net performance is 30 Mbps download, and between 0.3 and 2.0 Mbps upload. If I start in safe mode with netorking, I get download and upload speeds of 25-30, my contracted speeds. Obviously, something loading in the full mode interferes with upload speed. I have tried restarting in safe mode with all of the items checked in the services and programs tabs in msconfig, and still get excellent up and download speeds. How can I figure out what is interfering with my upload speed in normal mode, but not in safe mode?

Use msconfig to determine what is causing the problem

How to use msconfig in Windows 7

Click on Start then Run, type msconfig and press Enter.
Click on the Startup tab, record what is currently starting then click the Disable All button.
Reboot and see if it runs better.
If yes then use msconfig to enable several items at a time till you find the culprit.

If no, start msconfig and click on the Services tab.
Check the Hide All Microsoft Services box, record what is currently starting then click the Disable All button.
Again, do a regular boot, see if it runs normal.
If yes then use msconfig to enable services till you find the culprit.

Once you've found the culprit, uninstall it or find out how to eliminate it from your system. Simply disabling it in msconfig is a temporary fix at best.
Enable everything else you disabled.

None of the non-Microsoft services are involved. I disabled them one at a time, and did not get any improvement. If I disable all services (including the MS ones) I have no internet connectivity at all. Where do I go now?

It only took about 12 hours, but I solved it. My motherboard (ASUS) comes with software that allocates priorities to internet-using programs, and apparently it gives very low priority to brief uploads, like speed tests. I turned off the software, and all is fine. Thanks for the help here - it got me to rule out lots of things, and gradually I narrowed down the possibilities.

Do you have a link to info on that ASUS feature? I'd like to read about it if possible as I've never heard of anything like it before.

The feature is called "Network iControl", and installs as part of the motherboard driver package. It is almost perfectly undocumented by ASUS, but there is a youtube video at ASUS Network iControl Demo + BLOOPERS! - YouTube that describes it, and makes it look simple. Not so much!

Many thanks, interesting but obviously does not work well.