Thanks for the informative reply. Explaining the reasoning to us and being transparent about the situation is a huge plus in my book for any company.
wb_Intel wrote:
Assuming, we recommend you the one of the following solution (starting from the best one):
1.) Disabling ME FW /AMT if it's not needed
2.) Doing some experiments and decreasing AlternateSemaphoreDelay value to achieve smaller delays
3.) Setting AlternateSemaphoreDelay to 0 to enable the older wait mechanism from driver 12.10.28.0
I am on Windows 10, and I have the latest Windows 10 network controller drivers installed (from 6/2/2015). My motherboard is an Asus Sabertooth Z77 and I looked through my BIOS and it has no option anywhere to disable Intel Management Engine unfortunately. I did uninstall the Intel ME software though, but that didn't help as I'm still getting DPC spikes. 
With regards to the AlternateSemaphoneDelay, is this a string key or a DWORD key? I tried adding it but didn't see any effect really. Is a PC reboot needed or can I just disable and re-enable the network adapter?
EDIT: I just completely uninstalled the Intel network driver and Windows 10 seems to have reverted to a default driver which no longer causes the stuttering...so I'll leave it like that for now.