Emsisoft is a dual engine / dual definition antivirus using Emsisoft Antimalware + #1 rated Bitdefender A/V engine. By combining and optimizing the dual engines, Emsisoft has much less overhead on a PC, than Malwarebytes + any A/V combined. According to Emsisoft, they have a 99.9% ratio at blocking CryptoLocker due to Bitdefender's superior behavioral technology.
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Most likely yes, assuming that you're using Windows 7, 8 or 10 - with the latest service pack installed. All features are fully functional on x64 systems too. While running, Emsisoft Anti-Malware uses about 200 MB of your RAM which is quite low considering the 10 million signatures that it must load. If your PC has at least 1 GB of RAM, this will be perfect.