Need Help on PC comparison

I'm currently looking for a desktop computer that can meet this game's requirements (Sims 2) with minimal or no lag.


Ram-256 MB or more (512 MB for Vista)
Graphics-
Card must have atleast 32 MB (64 MB for vista)
Ati Radeon 8500+ (9600+ for Vista)
Nvidia Geforce2 GTS+ (6200+ for Vista)


HP Pavilion A6600F(FK792AAR)$329.99

OS-Windows Vista Home Premium
Processor-Intel Pentium dual-core E2200(2.2GHz)
Memory-3GB DDR2 800
Hard Drive-320GB SATA 7200RPM
Optical Drive 1-SuperMulti DVD Burner with LightScribe Technology
Graphics-NVIDIA GeForce 7100 Graphics with TurboCache with 128MB dedicated graphics memory. Up to 1343MB Total Available Graphics Memory as allocated by Windows Vista

Or

Gateway GM5688E $329.98

OS-Windows XP Media Center Installed + COA
Processor-AMD Phenom????????? 8400, 64-bit triple core processor

* Operates at 2.1 GHz
* 2 MB L3 cache
* 3600 MHz system bus

Memory-2GB 2048 MB DDR2, 667 MHz, (PC2-5300) dual channel memory
Hard Drive-320 GB, 7200 RPM, SATA II hard drive
Optical Drive-DVD?????????RW, 18X super multi-format dual layer drive
Graphics(customized)-Ati Radeon Hd3450 256mb Ddr2 Dvi / Vga

I'm pretty sure both are decent choices for the Sims 2 but I want to know which of the 2 is the best. Considering that it's only a penny of a difference and that I don't have much experience with Graphics cards I can't exactly make the accurate choice. And if you happen to stumble on a better deal, feel free to let me know [:)]