As I've been playing the demo, I've noticed that even using that even when following the guidelines given in the troubleshooting guide, Amnesia is near unplayable. I also checked my output on the Rendering test again, and everything came out fine, though at tests 11 and 15, the fps dropped to around .2.
My system is a notebook with a Geforce 7150/nforce 630m, Turion dual core 2.0 GHz AMD processor, and has 3.0 GB of ram.
I've attached the hpl log file, because though it might be the hardware, it may also have something to do with the warnings I've gotten.
Also if you edit the main_settings.cfg there is an option to load the debug menu. Once that is on you can get access to the debug menu by pressing F1 while in a level. When it gets low try and note the player position, etc.. and what the frame time is.. (Not the FPS, but rather the time it took to render a frame).
The game should run fine on that card..(around 30FPS at 800x600) I personally have been building the linux port using an Nvidia 7300 card. do you have Compiz running at all? as that will slow things down considerably.
Developing away on one of
Multiple Macs running 10.6, 10.7, 10.8, and 10.9.
Linux, 8-core AMD, 8GB RAM, Fedora 18, nVidia 450 1GB
I've done some work with my system, and I think it's an issue with Powermizer. A number of my other games are doing this too (I usually don't play too many games, so I hadn't really noticed till this one).
I say that because every time I hit the login screen, powermizer knocks my performance level down from 2 (ie max) to 0 (min). So that's likely the cause of my issue.