Adding more storage....should I condiser a RAID system

Hi, I want to add more hard drive space but I question if adding more hardware will reduce performance of my PC So are there other ways to use multiple drives (maybe a RAID)? Any way any input is appreciated.

Specs: Processor Model : AMD Athlon(tm) XP 2600+ Speed : 1.96GHz Model Number : 2600 ----------------------------------------------------

Mobo:Asus A7N8X Deluxe ======================================================

Chipset Model : ASUSTeK Computer Inc nForce2 AGP Controller Bus(es) : AGP PCI USB i2c-SMBus Front Side Bus Speed : 2x 170MHz (340MHz data rate) Maximum FSB Speed Max Memory Speed : 2x 200MHz 2x 200MHz ========================================================= Twin Wintec Dual DDR---512 MB ========================================================= Memory Module Properties: Module Name Wintec Serial Number None Module Size 512 MB (2 rows, 4 banks) Module Type Unbuffered Memory Type DDR SDRAM Memory Speed PC3200 (200 MHz) Module Width 64 bit Module Voltage SSTL 2.5 Error Detection Method None Refresh Rate Reduced (7.8 us), Self-Refresh ========================================================== Drives: Hard Disk : WDC WD12 00BB-53CAA0 SCSI Disk Device (112GB) Hard Disk : WDC WD20 00JB-34EVA0 SCSI Disk Device (186GB) Hard Disk : WDC WD20 0BB-00AUA1 SCSI Disk Device (19GB) Hard Disk : WDC WD20 0BB-75AUA1 SCSI Disk Device (19GB) Hard Disk : WDC WD25 00JB-00FUA0 SCSI Disk Device (233GB) Hard Disk : WDC WD40 0BB-00CLB0 SCSI Disk Device (37GB) ==================================================== All drive are on WinXP Promise Ultra100 TX2 (tm) IDE Controllers NO drive is on IDE connections Hard Disk : WDC WD60 0BB-32CXA0 SCSI Disk Device (56GB)

Total is 624GB (38GB excluded - 2 20GBs- One drive for OS and other drive I use for Programs ONLY). =============================================================