For many user that is new to VPS (Virtual Private Server) are often confused with the terminology that VPS provider use. This is because VPS are different from real servers, as you might know VPS are virtual server that is created on a real server so one host server can run several virtual servers. Some of those terminology are guaranteed memory and burstable/bursted memory that you might have heard when searching VPS hosting.
Guaranteed RAM is the amount of memory that is allocated for your virtual server, this is the fixed memory that you get automatically when you purchased a VPS hosting plan.
Burstable RAM is the maximum memory allowance that your VPS can use along with your guaranteed memory as long as the spare memory is still available for you to use. For example, in a virtual server where your guaranteed memory is 256MB and your burstable memory is 1GB that means you have access up to 1GB of unused memory along with your guaranteed 256MB of RAM. This is possible because other VPS user that you shared memory with are not using much RAM.
Burstable/bursted memory usually only available on Linux virtual servers, although some also say that Windows virtual server also provide burstable memory. This is something that you could consider when choosing your virtual hosting.
Now that you know what guaranteed and burstable RAM is, you now have additional knowledge that you can use to successfully pick the best VPS for your business from a lot of provider out there. Even though the service provider do not provide you with the information about their burstable RAM policy, you can always ask them through their website or send them an e-mail and if they don't give a satisfactory answer you can walk away.