Okay, first of all, all the information I can find says that.. for photoshop performance..
In most benchmarks, the Athlon64 are tied with the Prescott for photoshop performance at the same rattings, with the Pentium-M slightly lagging. But the laptop should be much faster than your AthlonXP.
That being said, a serious photoshop workstation as well as a 3d rendering station should consist of a high frequency Pentium-4 or Athlon64. The Pentium-4 seems to do well in 3d mark, the Athlon64 in some 3d rendering programs. Both have similar performance in photoshop. But you really need to research *your* specific applications, as there are massive exceptions to these 'General' rules of thumb. Like, the Athlon64 hands the P4's ass to it in Adobe premiere, while in Roxio Video Wave, the P4 3.4 inches past the mighty Athlon64 FX-55. Do research on your applications and make intelligent decisions based on that. At any rate, that 1.6GHz Pentium-M will be handily beaten by the majority of mid range Pentium4s and Athlon64s.