My computer has a strange issue when playing games that load assets on the fly. Perhaps I'm looking in the wrong places, but I seem to be unable to find anyone with a similar issue.
In case it's not clear, I'll note some examples. In Source games, the mapper is able to optimize things by telling the engine when and where to hide objects so that they are not added to the scene until you round a corner, or open a door. My computer chokes when it comes time to load in these objects. Take Portal 2 for example. Once the loading screen for an area goes away, I'm thrown into the level. Immediately, I'm greeting with a frozen screen, and stuttering/repeating audio, for about a second. Once that passes, everyone continues on all hunky-dory at full framerate. Then I walk up to a door, triggering it to open. Another good second of stillness and stuttering audio as it loads in the room on the other side. If you were to watch anyone else play the game, this would never happen. Anyway, this I can tolerate. It's annoying, but it doesn't really interfere with gameplay. Now let's game a game that constantly loads as you progress, Sonic Generations. Standing still, I get a silky smooth framerate. But as soon as he begins to run forward, loading more of the level, I drop to <1 FPS, making it utterly unplayable. More and more games seem to be doing this nowadays, which is why I'm finally getting serious about troubleshooting it.
I highly doubt these pauses are programmed into the games themselves. Loading screens are designed to run smoothly as data is loaded, and on any other machine, they do. Using Sonic as an example again, even the moving parts on its loading screens are extremely choppy until the load completes.
I had built this computer nearly four years ago, and have had this problem since I started using it for 3D gaming. Since then, I've replaced my motherboard, HDD, and graphics card, due to them dying. (Case fans stopped working one day, and the HDD was a whole 'nother deal.)
Running Win7 Ultimate 64-bit with Aero on, on an Intel 2.5Ghz quad core, with 4GB of RAM, and an nVidia GTX 460.
Thanks a ton, everyone!
Update: It's become apparent that I am getting a heapload of page faults. Average of 170,000 per second with Sonic Generations, average 70,000 during loads with Portal 2, and a very steady 30,000 while watching a stream at Livestream.com. According to Resource Monitor, these aren't even hard faults. I'm kinda curious how these numbers compare to everyone else.
Addendum: Might as well add another example, and a potential symptom. First, a racing game called Trackmania. In a solo race, there are no noticeable page faults, (beyond what other programs may be producing) and the game runs silky smooth. When playing online however, I get massive hiccups (and page fault spikes) at frequent-yet-random intervals. I'll be racing along, game will pause for a good second or more, and will resume with my vehicle upside down in a crumpled mass next to a wall. Hiding the cars of other players doesn't fix the problem either.
As for the potential symptom... I've avoided mentioning it because I was afraid it might be an unrelated issue, and didn't want to send troubleshooters down the wrong path. At this point, why the heck not mention it? Basically, my computer will downright completely freeze after watching video for some time. Looping audio, entire screen (including cursor) non-responsive, num-lock won't toggle, can do nothing but a hard shutdown. It can trigger in minutes, or hours. Typically, the larger the viewport is, the sooner it happens. As long as hardware acceleration is on, full screen Youtube videos are safe.
Full screen Youtube with hardware acceleration on does not seem to produce page faults. It does when windowed, however. Livestream always produces page faults, full screen or not, accelerated or not. Games never seem to freeze my computer like this however, despite generating loads of page faults themselves.
(Changed title from "Graphics become choppy when game assets are loading in the background" to "Getting gratuitous amounts of soft page faults when loading games and watching flash video.)