97civkid

Hey guys, like it says, my 97 civic with stock y7 is burning oil, motor has aprox 350km, I bought this car a year ago and have never noticed much consumption, dono what oil the prev owner used but I use 5-30 f1 with sythetec wear guard, would that be sythetic oil? But just resently noticed quite a bit oil being burned, switched to 10-30 castrol gtx, now don't notice it as much, when i did notice it burning was only at high revs especially off rev limiter, would it be rings?