Burstable and Guaranteed memory on VPS
One of major benefit of getting a VPS is that you can have Guaranteed memory aswell as Burstable memory at your disposal. Guaranteed Memory can be defined as the usable memory which is allotted to your VPS. Such memory is available for you at all time. Also you can have Burstable memory which is set for your webhost for your VPS.
Its a maximum limit for the memory which can be made available for your VPS. Thus for some reason if the allotted guaranteed memory gets exhausted, you can use the memory up to the limit of allotted burstable memory and your VPS would run smoothly. For eg if your webhost have allotted 256mb of guarantee memory and 1024 of burstable memory then you can use remaining 768MB of memory if your guaranteed memory is completely used up. 
This is a major advantage of getting a VPS hosting account which will ensure your server would run smoothly even if few applications are consuming more RAM. Such burstable RAM can be used when they are in need of any extra memory..
Its always better to have a good guaranteed memory for your server so that your VPS would work properly. This burstable memory is not easily available as it can only be obtained if there is lapse of guaranteed memory for your VPS. You should always look with your webhost for what guaranteed and burstable memory is allotted to your VPS and should check if its sufficient for your applications and scripts.
