Recently, I've noticed that in some games I've been getting framerate issues after some time playing them.
Firstly, I'll describe the issue in dishonored.
I play with minimal graphics settings at 1920x1080, due to my somewhat substandard hardware (GTX460m, i7 Q840m, 4 gig ram). The game runs initially very smoothly, but after a play duration of between 5-10 minutes, A strange effect occurs. Firstly, and most noticeably initially, the audio begins to 'double up'. By this I mean that I hear everything more than once in quick succession, creating an echo effect. It's quite hard to describe, but it's as though every sound is played repeatedly at 0.1s (I estimate) intervals. At this point, the game also begins to tank in framerate down to 10-15 fps. I have also managed to associate this degeneration with loading new zones, or reloading the current zone from an autosave. When I first load in things are typically fine, but upon loading a new area or reloading the current one things tend to get worse. After each subsequent reload things seem to get worse. Also noticeable is that the game seems to have difficulty loading something (possibly textures?) when I move the camera after a reload. If I reload next to a wall, then move my mouse to observe the wall directly, the framerate drops to between 1 and 5 fps, depending on how far away it was (lower for closer). The game seems to do this the first time I look at each thing after a reload.
The only similar effect I've ever noted to the one I just described is in Diablo 3, where after launching the game the first time I observe a spell effect it causes a very notable stutter in the game. These days, when I load in the first thing I do is use my abilities one after an other to get the stuttering of my own spells done and dusted. The first time I use each spell the game usually freezes on a frame for 500ms-1000ms I estimate. I'm not sure if this is at all related to the dishonored effect.
I notice framerate slowdowns on some other games but those were the two instances I felt most definite about what was causing them.
My graphics card's driver is up to date, and runs at expected speeds in GPU-Z. It also benchmarks fine. My processor likewise seems to be operating as expected.
Any suggestions? I'd like to exhaust all possibilities before attempting a reinstallation of anything; I'm currently in Myanmar and the internet is pretty slow. Installing a large game would take several days and render the internet unusuable for anyone else in the house for the duration.