Avira is by far the best and I've tested almost all of them. It catches as much as possible, not a huge memory hog and interface makes more sense. Also, importantly it doesn't just remove everything perceived a threat, I've had false positives permanently deleted by AV, I never could get the files back - that's not how AV should work.
Check your Task Manager/Processes to see how much RAM Trend Micro is using. One of the reasons I installed Bitdefender is because it's claimed to have a "light impact" on the system. Seems some truth to that statement, as Bitdefender's "bdagent" is using 69MB on my rig currently while Kaspersky was at least double that. (Over the years I've had half-dozen different AV software. They have all been good at first... until they developed problems, became inconvenient or annoying.)
Question... what is the safest way to open an attachment on an email? Is that what the "sandbox" is for?
A sandbox is a virtual environment. Any changes malware makes to that virtual environment are negated when the system is shut down as nothing is written to non-virtual disk. Some browsers try to incorporate some of sandbox's features. Seems a program like Sandboxie is a good idea for surfing the net. When I checked into it a few years back, the one weakness was that I couldn't mark a folder to "write through" the sandbox.... for archiving stock market data in MetaStock. Don't know if that has changed.)
That's not the actual memory usage. All AV nowadays use multiple processes. The agent is just the frontend, just the GUI basically, the actual AV is in the hundreds of MB.
Antivirus on a trading computer - no way! Have not run an AV for maybe 5 years now. I do a daily sweep for them anyway - amazing how clean your computer stays when not down loading free crap or surfing the porn.
I won't open email attachments unless I know who sent them. I then verify, either by text or phone, that they did indeed send them. I've received email attachments that were sent from individuals who did not know they were infected...until they started getting angry emails from everyone in their address book. I use MS security essentials currently, with periodic scans using MS security scanner, free Kaspersky scanner, and Malwarebytes. Years ago I caught the re-direct (Alurion) on an XP system. I was running Mcafee at the time, but of all the free scans I ran, found it with Kaspersky, and removed it. I switched to essentials after catching a virus on my current SPX 64bit system, again while using Mcafee. MS Scanner found it, so I loaded up essentials and it quarantined it. decided to make the switch, especially since it's free. So far so good. No issues with bogging down, except occasionally if running a full scan with any of the scanning software mentioned. I use free Avast protection on my tablet.