You are seriously underestimating the sheer amount of work it offloads from the CPU. I don't see a single game on this planet that runs in real time, produces small physics particles, and runs on a normal CPU that produces the same standard that PhysX achieves. And trust me, if you've played GTA4 on PC - you know how much open world games need the CPU even when nothings happening. My CPU runs into problems occasional and it could not be called 'slow' by anyone except purist enthusiasts.
I'm going to contend that point on the grounds of technical ignorance. I'm actually involved in University level GPGPU research so I'm a bit more qualified to talk about this than most. First off GTA4 performance issues have nothign to do with the cpu being over taxed and everything to do with a terrible port on the part of the devs. The number of crashes and graphical errors support this. GTA4 for the PC was and still is to a good degree half backed and poorly supported. As for physx, modern cpus, let alone oens from the beginning of this decade are nowhere close to being over taxed in games, let alone physics.
What you are seeing with your 4850 are mesh objects that are scripted and don't have collision or mass or anything to do with physics. All the debris and ruble from grenade explosions does nothing in non PhysX games, it looks pretty but then it seemingly vanishes and fails to interact with any object it should of hit. PhysX actually enables real time physics for all them pieces of debris, not just some scripted event. I am almost positive Havok physics is perfectly capable of doing everything PhysX does. But we don't see it, because CPU's aren't powerful enough - You only rarely see Havok physics used in a similar way PhysX is used in the above video, but it is not anywhere near on the same scale.
Whether you appreciate it (which you clearly don't) is another matter entirely.
That isn't entirely true. Some games utilize this, however the level of scripting in games has been going down continuously since about 2004. Early versions of havok, like that used in HL2 and oblivion were pretty limited, but it is much better now, and less of a system limitation and more of a developer consideration. The reason physx games tend to have more of this is because Nvidia pays these guys to add it. Which to be honest are things that most people don't need or notice. The only physx game that I have seen that really adds anything is Mirror's edge, and the effects are easily overlooked and without AA it looks terrible.
The fact that you even said that cpus aren't fast enough shows you do not have a basic understanding of digital logic. Allow me to explain. CPU's aren't taxed by games most of the time, and really the only time they are is when you have a game like SupCom with a large number of AI, since that is cpu controlled. physics is relatively (for a computer) simple math done very fast, and that happens to be what computers are very good at. Mundane and repetitious math calculations, what they aren't good at is simulating intelligence and rendering 3 dimensional worlds because you are forcing a digital system to replicate something that is analog in nature. This is why cpus tend to have it so easy in FPS games, they get to do the easy things like process controller inputs, sound and physics all light loads that are very digitally inclined. Video cards have to emulate shapes and effects that are anything but digital. Light for example acts in very complex and hard to quantify ways. It is a particle and a wave at the same time. Or take depth of field for example. The engine has to calculate the distance an object is from you and its relation in perspective to your line of sight and then blur it accordingly trying to mimic the limitations of the human eye. That isn't a cut and dry algorithm with a simple answer. To make things look organic you have to make the logic complex to give you those unexpected and "organic" numbers. Digital logic isn't made for this, it is very expensive resource wise.
Also, cryostasis looks like crap. The graphics are high end, but the execution was terrible, no artistic direction here. It makes Half Life 2 look modern by comparison. No amount of physics can fix that. And what is with all of the cryostasis love? It came out 2 years ago, are you just now hearing about it? The game was laughed at by reviewers, if you want to make a strong case for physx than use a game that did well like mirror's edge. not a "Snail-paced frozen nonsense" -Pc Gamer UK
http://www.metacritic.com/games/platforms/pc/cryostasissleepofreason
cryostasis
HL2 Lost coast