I haven't seen a discussion like this after a search, and I couldn't find anything on Steam Support related to these issues, so I figured I would make my own thread about it. This isn't isolated to Portal 2, I've noticed it happening in any single player Source engine game (except Left 4 Dead 1 & 2, for some reason). I can play just fine for a while, but then I get random lag spikes for 60-70 seconds at a time. For example, I'll play just fine for 10-15 minutes at a near-constant 35-60 fps, but during these lag spikes, the framerate will drop to 5-20 fps. I may have deduced these spikes to an issue related to DirectX 9. I say this because, in older source engine games that support DX8 (HL2 Series, Portal 1), if I switch to DX8 modes, these lag spikes cease to be. If someone could help me with this issue, I would be grateful. Thanks in advance!
System Specs (in case they help, it's a dinosaur, don't laugh at me) CPU: Pentium 4 3.0GHz GPU: XFX GeForce 9600 GSO 768MB RAM: 1 GB OS: Windows XP Professional SP3 (32-bit) HDD: 160 GB