Playing Day of Defeat 1 based on the old HL1 engine is slower than any Source-based game i played - TF2, No More Room in Hell (HL2 mod), Day of Defeat (HL2 mod).
DoD 1 with vsync on gives low framerates, 20 something sometimes, while the others mentioned above run smooth with vsync on.
Why is this?

The hardware is A8-6500 (with its Radeon HD 8570D IGP - it uses the r600 driver), but it was the same with A8-5500 before it. I run Steam on Debian 64 bit, with the kernel, mesa, drm, xf86-ati compiled from git.