ThamesG,
What file type is your video? For 1 minute 35 seconds, a HQ MPEG2 should(I expect) weigh in at a heck-of-a-lot less than 3 megabytes(if that's what you mean by 3M). You have AVI(monstrously huge file size), MPEG2, WMV(stop me if I'm getting warm here), QuickTime, H.264 AVC, H.265 HEVC or X AVC S, Under H.264 AVC you have further options, M2TS, MP4 or MKV, Under H.265 HEVC you have the same choices and under X AVC S, you're stuck with MP4. So one of these options will cut your file size down, it's just a matter of trial and error to see which file type is going to do the job.... In other words, "suck 'em and see!" Even before you begin to render, clicking on each option should tell you how big the estimated file size will be. Just avoid AVI! Last time I tried rendering a short piece in AVI it ended up as a whopping 8+gigabytes for a little over 1 minute, 45 seconds....Ouch!