Please compare Emsisoft and Avast in RAM and CPU Usage

I'm on an old system and could use a lightweight AV now that my Advanced System Care Ultimate trial has expired. I am finding Ashampoo Anti-Virus heavier than desired.

Operating System
Windows XP Home Edition 32-bit SP3
CPU
Intel Pentium 4
Northwood 0.13um Technology
RAM
2.00GB DDR @ 166MHz (2.5-3-3-7)
Motherboard
Dell Computer Corp. 0G1548 (Microprocessor)
Graphics
Default Monitor (1280x1024@60Hz)
Intel 82845G/GL/GE/PE/GV Graphics Controller (Dell)
Storage
74GB Seagate ST380011A (ATA) 28 °C
3GB Lexar USB Flash Drive USB Device (USB)
119GB PNY USB 2.0 FD USB Device (USB)
Optical Drives
SAMSUNG CD-R/RW SW-252S
Audio
Unimodem Half-Duplex Audio Device
Anti-Virus
Ashampoo Anti-Virus