Ready Boost was outdated practically by the time it was made. Ready boost essentially just says "use this device before the pagefile on disk". This means that to see an improvement, you'll have to be already running out of RAM. If you frequently find yourself running out of RAM (very unlikely w/ 4GB unless you know you are-- heavy use of adobe software, VMs, 3D rendering, etc), then you'll be making active use of your pagefile. Now for ready boost to help out there, your Ready Boost drive will have to be faster than the drive your pagefile is on (by default the drive Windows is installed on). Most hard drives these days will outperform any USB device unless it's a USB 3.0 performance drive (at this point you should've just gone with a bunch more RAM or an SSD for your pagefile). Even if all of this were the case, you would only need to allocate enough space for how much extra virtual memory you're using, which should never run more than a few GB even under heavy loads (unless you know what you're doing and are running very very heavy datasets such as scientific experiments or corporate data crunching).
tl;dr: no it won't help you at all. If you actually even have a problem in this area, buy more RAM instead.