avast! Antivirus software writing to SSD a lot during scan

Hi guys,

I installed avast! Antivirus on my Mac, not to protect my Mac specifically but to prevent it from passing on Windows malware to other computers or into my Windows partition. During full system scans, I notice that it reads a lot of data from the drive (which I would expect) but it also writes up to 40GB of data to the SSD by the end of the scan! I know that writing excessively to SSDs can reduce their lifetime (although I tried calculating its expected lifetime using my daily write figures, and I should have at the very least another 10+ years of use, which is more than enough).

My point being, why is avast! writing to the disk so much during a scan? Is it caused by heuristic scanning or something? I don't want to put unnecessary strain on my SSD, even though I know Apple SSDs are generally pretty durable.

Thanks.

Note: Kindly don't give me a lecture about installing antivirus software on Macs – I know that it isn't strictly necessary but I explain why I use it at the start of my post.