CPU upgrade, will my PSU handle?

Currently using an E1400 with an HD4650, 2GB of DDR2667 RAM, nVidia nForce 610i, 2fans (CPU/Extra), 1x 320GB HDD (SATA). My PSU is the default 200W 15A(12v) PSU.
Will it handle an upgrade to an E7200?
Reading this, it seems that the E7200 with an 8800GT, 2GB more RAM, and a 10k RPM HDD uses 159 Watts at load. It'd be reasonable to assume that my HD4650 and 2GB of ram would use much less power, then, right?

Thanks!