I have a workaround for 100% CPU / lag spikes that dramatically reduces them, both how often they occur and how long they last: No downloads or installs are required, but this solution might limit your CPU too much if you have an Intel Core i5, and not a Core i7. I don't have a Core i5, so I don't know which threads you need to disable, but I am guessing the last two ones. Quick explanation for computer experts: Use CPU pinning on starcitizen.exe in task manager to disable your last core for Star Citizen, i.e. the two hyperthreads on the last core, both threads 6 and 7 on a quad-core. Hyperthreads are distributed across cores in the pattern (0, 1) (2, 3) (4, 5) (6, 7), etc. I have tested and verified this on an Intel Core i7-4790K, but I am hoping it will work for other CPUs as well, provided you have cores enough to run the game after disabling one. Oddly, other patterns of hyperthread disabling don't work for me, but feel free to experiment! Explanation for everyone else: Start Star Citizen, and alt-tab back to desktop once you are in the game main menu Right click an empty space in your task bar, and select "Task manager" (The task bar is the bar, usually at the bottom of your screen, where the Windows button and running programs show up) Select "More details" at the bottom of the Task Manager Choose the "Details" tab Find StarCitizen.exe in the list Right click StarCitizen.exe and select "Set affinity" Unselect CPU 6 and CPU 7 Click "OK" (you can leave Task manager running or not, as you please) alt-tab back to the game Enjoy! You have to repeat the process every time you restart Star Citizen. If this doesn't work for you, there are some other workarounds that might help. One method I got from <insert attribution here> in #general on the PTU servers and have had success with involves downloading an application-targeted CPU limiter to use on StarCitizen.exe: That allows you to limit the overall processor performance available to StarCitizen, and I have gotten good results by reducing the performance available to Star Citizen by 5%. The limiter program going around the chats is: "Battle Encoder Shirase", but I have nothing to do with it, and can't vouch for its safety in any way. You can find "Battle Encoder Shirase" at: http://mion.faireal.net/BES/#download In the posts below, @Valkyrie, has yet another method you might want to try out. Edit, 2022-09-18: Since I still see people posting about this, I want to point out that I don't think this post is relevant any longer. When I made the OP, SC was working on the first version of landable planets, this is pre Alpha 3.0. To do that they were introducing Client side Object Container Streaming and not only was OCS terribly buggy, the game was also very close to single-threaded only. Since then, OCS has become an old, stable system in extensive use, and a huge amount of work has gone into both multi-threading and thread management. CPUs have also developed radically (I was running an Intel 4790K at the time). So I would be very surprised if this thread has any relevance at all now (it would be extremely bad luck if CIG happened to have recreated the same bug under entirely different circumstances).