I still have my 13" Lenovo Yoga with a i7-4500U and 4400HD embedded graphics. It's been a long while since I used it with SL (as you might imagine!), but I'll try it out tonight and report how it does in a number of activities.
So I spent about 90 minutes tonight wandering around
doin' stuff in Second Life in locations not too populated, on my nearly 8 year old laptop.
At first I tried Mid graphic settings. I did a bit of walking and such, but there are now a lot of walls with my avatar's face imprint. I was maybe reaching FPS in the high 20s at the best of times.
Shifting to Low graphic settings helped. I was able to move around a lot more confidently, with only occasional dips and burps in the framerate. Much of the world looked, as one would expect, bad. Or plain, if you will. But I was able to get around, chat, etc.
I had a couple drops during teleporting to different sims, but I was some distance from my wireless router, so this likely had more to do with that.
My takeaway: Don't do Second Life on an 8+ year old laptop with embedded graphics unless you have no better alternatives. It would certainly be a horrible first impression of it. Long-time SLers might be able to take it in stride, assuming it's not for long durations inworld and more of a backup option.