BF3/4 CPU insensitivity versus dedicated Physx

[vandist]

No doubt BF3 is a CPU hog, I make the assumption the reason for this is what Nvidia calls is PhysX (explain or correct if I'm wrong). I'm going to assume BF4 will perform better in terms of FPS with more CPU power.

Question - does BF3 become less CPU intensive with a low end GPU dedicated for phsyx?

If so considering BF4, what GPU (nvidia) will do the job to take the pressure from the CPU?

 

[hizodge]

Battlefield 4 has no Advanced PhysX support. All physics calculation will take place exclusively on the CPU.

 

[17seconds]

There is no PhysX anything in the Battlefield series. All physics, including destructible environments are handled by the CPU. Battlefield 3/4 use the Frostbite engine, which has its own method of performing physics on the CPU, which is unrelated to Nvidia's PhysX. Battlefield 3 is not known for being a CPU intensive game.

 

[vandist]

There is no PhysX anything in the Battlefield series. All physics, including destructible environments are handled by the CPU. Battlefield 3/4 use the Frostbite engine, which has its own method of performing physics on the CPU, which is unrelated to Nvidia's PhysX. Battlefield 3 is not known for being a CPU intensive game.

Ok so that sorts the physics, another GPU dedicated for it will have no benefit then.

As for the CPU intensity - I beg to differ, I personally find it is pretty heavy. There are only two games that I own that pretty much push my CPU (I7 2600k) to 58C and upwards of 80% utilization, that's BF3 and Batman Arkham City.

Maybe it is subjective depending on the CPU, I'm not going to pretend to know but what I do know is my CPU gets really pushed on large Multiplayer maps in BF3.

http://forums.anandtech.com/showthread.php?p=33514470
Look at post number 30.

 

[17seconds]

Another thing you can do is run Afterburner while playing the game and see what the GPU usage is. That will tell you the amount of bottlenecking there is between your GPU and CPU. Anything below 90% GPU usage is an indication of a bottleneck with your CPU. Just FYI.

 

[magrospic]

That leaves me very confused!

Oddly enough, I was having major trouble with BF4 until I dedicated a whole GPU to Physx...

Rig:
-3960x @ 4.4GHz
-X79 Rampage IV Formula
-4x4GB G.SKILL RIPJAWS-Z PC3-14900
-2x GTX 680 2GB SLI
-256GB Samsung 830 SSD

The game would start fine but then as soon as someone fired a shot or two (resulting in some kind of Physx), the frames would drop dramatically down to 1-2 even after dropping the resolution to 1024*768.

After hours of hardcore (extreme!) frustration I switched the Physx from Auto-Select to the CPU but that didn’t work. Then I switched it to one of the GPUs (non-dedicated) and it got considerably better. Finally, after dedicating an entire GTX 680 to Physx the game now runs @ 4K Ultra… on a reduced resolution scale to be fair, but looks mind bogglingly tasty.

I’d like to believe that the Physx is CPU bound only but this really seems to work for me and definitely looks like it is GPU reliant, even though I hate anecdotal evidence!!! It might also be worth mentioning that I have unmatched GTX 680s (both reference with same clock speeds and memory), which work without issue on all other games including BF3.

Hope this information helps if anyone else has a similar issue

 

[magrospic]

PS I was using 'Physx' in the same way (rightly or wrongly) as 'Googling' or 'Photoshopping' because BF4 is more affiliated with AMD. Either way the physics calculations seemed to work correctly when dedicated to a particular GPU. All too confusing for me

 

[17seconds]

You most likely were experiencing SLI problems because, as mentioned before, there is no PhysX in the Battlefield series. Simply dedicating a GPU to PhysX in the control panel has the effect of disabling SLI. Do yourself a favor, if you do play actual PhysX games in the future, put the selector back on Auto so that it will work properly. Then try to figure out what's going wrong with your SLI system; it could be drivers, incompatible cards, or some other setting.