[Womble]

Hope someone can enlighten me with my problem. At the moment I have 1 stick of 512 DDR SDRAM, but I have been given 3 sticks of 256m PC100 100mhz. What I would like to know is what is the best set up to have?. System spec is below.
All comments gratefully recieved

Processor
Model : Intel(R) Pentium(R) 4 CPU 2.40GHz
Speed : 2.40GHz
Performance Rating : PR2638 (estimated)
Type : Standard
L2 On-board Cache : 512kB ECC Synchronous ATC (8-way sectored, 64 byte line size)

Mainboard
Bus(es) : ISA AGP PCI IMB USB FireWire/1394 i2c/SMBus
MP Support : No
MP APIC : Yes
System BIOS : American Megatrends Inc. P1.30
Mainboard : P4VX4
Total Memory : 511MB DDR-SDRAM

Chipset 1
Model : ASRock Inc ProSavageDDR P4X333 CPU to PCI Bridge
Front Side Bus Speed : 4x 133MHz (532MHz data rate)
Total Memory : 512MB DDR-SDRAM
Memory Bus Speed : 2x 166MHz (332MHz data rate)

Video System
Monitor/Panel : Acer LCD Monitor AL1721
Adapter : NVIDIA GeForce FX 5600
Imaging Device : Hewlett-Packard PSC 750 Scanner