From personal experience, my computer is waaay under those capabilities. But SH3 seems to work well on mine. SH3 should be real nice on the machine you listed.
As for SH5, here's the *recommended* specs taken from
HERE
Intel Processor - Core 2 Duo E6850 3.0GHz
AMD Processor - Opteron Dual core 270
Nvidia Graphics Card - Geforce 8800 GTS 512MB
ATI Graphics Card - Radeon HD 4850
RAM Memory - 2 GB
Hard Disk Space - 5 GB
Direct X - 9