After upgrading TeamCity from 7.1.3 to 8.0.4, I've seen significant performance problems on my server: builds that took 1m20s are now 2-3 minutes, and running tests jumped from 7 minutes to 15-20. This behavior happens when I run the builds outside of TeamCity as well, and disappears when I turn off the Teamcity Server service.
I've checked cpu/memory/network activity, and nothing stands out. I downgraded to 7.1.5 and my performance problems disappeared. I installed a copy of 8.0.4 with an empty internal database and configuration, and experienced the same issues. I tried it with 8.0.1, same result. Installed to another disk, again the same. I then installed (an empty) 8.0.4 on another server and it is NOT experiencing these performance problems. They're both Windows Server 2008 with the same patches, although they have different hardware.
Any suggestions on where to look next or what details to provide? No antivirus software is running, windows search is disabled, and 7.1.5 works fine regardless.