Can anyone tell me how I can expect HL2 and Doom 3 to run on my machines?

Main

AMD Athlon 64 3200+
ASrock K858X (SIS Chipset)
512Mb 400Mhz Ram
Sapphire ATI Radeon 9800 pro Atlantis (128Mb)
160Gb SATA HD

Second (Laptop)

Pentium 4 2.53Ghz (Desktop Chip)
512Mb 266Mhz Ram
875 Chipset
ATI Radeon mobility 9000 64Mb
60Gb Ultra ATA 133 HD

Thanks In advance