Simple problem - no solution as of now. Insane spikes regarding my download speed. Guess a picture says it all:

It's ok for the first few 100M, then it drops to zero and just from time to time downloads some articles.
Here's the requested specs and some more information you might ask for anyways:
Version: 0.6.5
OS: WHS (v1)
Install-type: Windows Installer
Skin (if applicable): Plush
Firewall Software: None except Windows Firewall
Are you using IPV6? no
Is the issue reproducible? well... depends... on my system, yes ;-)
Hardware: HP Data Vault X311
Installed using this guide: http://wiki.sabnzbd.org/how-to-install-on-whs
Here's what I've done/tried:
-Disabled AV (WHS Add-In ClamAV)
-Disabled all NIC settings such as float control and stuff
-Set cache to 64M, 150M, ...
-First few 100M load fine. After that, the traffic gets bumpy... doesn't matter if it's less than a GB or a really huge NZB file.
-On other PCs on the same network it's fine, it's just my WHS that's causing me trouble.
All I get from the debug log is "delaying"..., but other users on this forum mentioned that their WHS with similar specs could easily handle max speed (even if I limit my speed to 1000kb/s I get these spikes). CPU usage is not an issue. Any ideas?

