Running LinuxMint 18.3Xfce from a flash drive

Hello,

I'm trying to run LinuxMint 18.3Xfce from a flashdrive. I said "trying" because this is the 5th O.S. and 3rd attempt at LM18.3.
Problem begins shortly after opening the homepage for the first time and/or running 'updates". After that, the lagging starts and it's debilitating. I've seen it take 4+ mins. just to load a browser, I don't know how long to install multi-media codecs because after close to an hr., I gave up, 1 game took 20 mins...well, your getting the idea. Now it's not the flashdrive(s) for I've tried 5 different ones, all reacting the same and the lastest drive in use is well less than 1 y/o and is 3.0. I've tested the drives after removing LM, Ubuntu, LinuxLite and PuppyLinux. All the drives, after formatting, performed as should (read/write tests). So, it's NOT the drives. OK, I used pendrivelinux to create all bootable O.S.'s. Couldn't use some of the other programs for some would not load the desired O.S. and some wouldn't create 'persistence". I'd like to get this fixed. I used to run Lm 17.3, but, foolishly, decided to "upgrade" and it's been hell ever since. You ask "why don't I regress to LM 17.3 again?", ...because I can't install the Opera browser of my choice in 17.3.(although I just may) Hoping someone here has some thoughts on this dillema.

Rick