About 70,000 people have died in the Syrian civil war over the last two years.
This is about twice the violent mortality rate of the State of Chihuahua in Mexico, which has the higheste murder rate in the world (about 111 murders per 100,000 people, per year).
On the other hand, Syria has a population fairly close to that of the United States during its Civil War, which killed about 1,000,000 people, give or take, over five years, a mortality rate about seven times as high. There were battles in both the U.S. Civil War and in World War I that killed that many people in a single day in a single location. This is despite the fact that Syria's population is much more dense, that a much larger proportion of the population is in or near war zones, and that far more advanced military technology (e.g. jet fighters dropping bombs) has been used in Syria.
I doubt that much of the difference in lethality between the wars of a century or two ago are mostly more lethal because of improved modern medical technology that is available now, although I'm sure that this has had some incremental effect. A better tactical understanding of how to fight an insurgency or counterinsurgency or any kind of war for that matter, with modern weapons, which was absent in the wars of a century or two ago, is probably a bigger factor.