PhysX F.A.Q. Compilation of questions I am finding throughout the forum.

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chizow

Diamond Member
Jun 26, 2001
9,537
2
0
Keys,

I'd be interested if you could find out if:

1) There's any plans to change existing titles using the cpu/software back-end solver for PhysX to use the gpu instead.

2) if doing so would improve performance any. This could be two-fold, by decreasing the load from the CPU in intensive/bottlenecked titles or actually accelerating existing effects.

3) if there's any plans to implement additional hardware PhysX features in existing titles that currently use software/CPU PhysX. I know its not likely as most Dev houses don't even have funds to publish a patch, much less a PhysX pack, but it doesn't seem like it would be too difficult if they're already using the PhysX SDK.

Thanks!
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
A: Nvidia is currently helping Eran Badit of NGOHQ.com with a porting effort to allow PhysX to run on ATI cards. How successful they will be without AMD's blessing is unknown.
Here are some links.

I am pretty sure that I read that both nvidia and AMD are giving direct engineer and spec support to eran. So AFAIK AMD is also in that boat (physX was originally targetted at AMD, but now it seems larabee is the real threat to both).
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
55
91
If you read it a the inquirer........ ;) . Otherwise, if you can find/remember where you read that, I can update the 1st post.
Everywhere I have seen on the web says AMD isn't cooperating with Eran. You can just google "Physx on ATI" or Physx on AMD".
But let us know if you find it.
 

Buttons

Junior Member
Oct 6, 2007
20
0
0
I'm a bit overwhelmed by it all, but here's my question:

If ATI does get on board with PhysX, will it be possible for them to implement hardware support into their existing cards, or would it only be possible in future cards which has been originally designed with PhysX in mind?

For example is it POSSIBLE that the HD4850 could gain hardware support for PhysX?
 

Blazer7

Golden Member
Jun 26, 2007
1,136
12
81
Originally posted by: keysplayr2003
Originally posted by: Blazer7
No they are not cooperating and you don't need to search the net for info on this. Just visit NGOHQ.com.

http://www.ngohq.com/news/1421...-radeon-hd-3850-a.html

I think that was posted on June26th. Things could have changed since then. I'll give the rest of the site a looksee.

The thread was closed on Aug 20 with no changes. AMD is still not helping them.
 

Sylvanas

Diamond Member
Jan 20, 2004
3,752
0
0
Any progress with PhysX on the IGP this weekend Keys? (sorry, don't mean to sound too pushy :))
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
55
91
Yes, well I wouldn't call it progress anyway. The IGP, when enabled, slowed performance down a bit even without using it for PhysX. There was some extra disk thrashing when the IGP was enabled due to it using 256 MB of my total of 2GB in a Vista rig. Vista is such a resource monster. So before I can have any conclusive benches, I need to add another 2GB to the system.

Update: Ok, I have another 2GB DDR2 I can borrow from another machine for a while. I'll keep you updated when I run the tests again.
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
55
91
Ok guys, some interesting developments (to some I guess).

System:
AMD Phenom X4 9550 2.2GHz
ASUS M3N-HT Deluxe 780a motherboard
2GB DDR2
9800GTX+
Windows Vista 32
Forceware 177.83

I've tested this system 2 ways. Once with 2GB DDR2, and again with 4GB DDR2.

Here is what I have encountered:

9800GTX+ Render + PhysX 4GB DDR2. IGP enabled (256MB DDR2 system memory used)
Min: 37, Max: 58, Avg: 46.284

9800GTX Render & 780a PhysX 4GB DDR2. IGP enabled (256MB DDR2 system memory used)
Min: 25, Max: 39, Avg: 31.737

--------------------------------------------

9800GTX+ Render + PhysX 2GB DDR2. IGP enabled (256MB DDR2 system memory used)
Min: 21, Max 46, Avg: 31.568

9800GTX+ Render & 780a PhysX 2GB DDR2. IGP enabled (256MB DDR2 system memory used)
Min: 0, Max: 32, Avg: 23.685

The benchmarks show two things.
1. The 780a IGP which GPUz shows as having 16 shaders and 4 ROP's slows down performance rather than just letting the 9800GTX+ handle everything on it's own.
This "could" be attributed to the IGP utilizing slower system memory, but would require a
discrete 16 shader card to prove/disprove. I havn't any at this time.

2. As anybody can tell you, Windows Vista is not 2GB friendly. Using Vista 32, I was only able to utilize about 3GB out of 4GB of installed system memory, with 256MB dedicated to the IGP. But far superior to the compared 1.7GB I was able to use with only 2GB DDR2 installed with the same 256MB dedicated to the IGP.

Just look at the difference in the benchmarks from 2 to 4 GB. Minimum fps on the 9800GTX+ Rendering & running PhysX almost doubled. 21 to 37. Amazed here. Disk thrashing obviously plays a huge role here. I noticed a quieter hard drive when benching with 4GB of course.


 

JACKDRUID

Senior member
Nov 28, 2007
729
0
0
ty Keys for the info..

I suppose that rules out free physx on IGP... How about a low end card such as 8600/8500/8400?

TYI
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
55
91
Originally posted by: JACKDRUID
ty Keys for the info..

I suppose that rules out free physx on IGP... How about a low end card such as 8600/8500/8400?

TYI

I did try an 8600GT for PhysX. All in all, minimum framerates were increased 25 to 30%.
I have benches on it in the Dedicated PhysX thread somewhere around here. I'll pull those numbers from that thread and place them here. We don't have to resurrect that thread now.
 

Sylvanas

Diamond Member
Jan 20, 2004
3,752
0
0
Thanks for the testing Keys, I will hold out another month or two for a 55nm GTX280 with something like an 8400GS doing the Physics instead of the IGP.
 

Chriz

Senior member
Oct 9, 1999
438
5
81
Has anyone tried using an ATI card for the primary GPU and a Nvidia card for the PhysX? Does that work if you use the workaround or under XP?
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
55
91
What workaround for XP?
I'm sure somebody here could try that setup though. Anyone?
 

aka1nas

Diamond Member
Aug 30, 2001
4,335
1
0
Originally posted by: Chriz
Has anyone tried using an ATI card for the primary GPU and a Nvidia card for the PhysX? Does that work if you use the workaround or under XP?

There is no workaround for Vista, it's a WDDM driver limitation. XP shouldn't have an issue mixing GPU vendors.
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
55
91
Originally posted by: aka1nas
Originally posted by: Chriz
Has anyone tried using an ATI card for the primary GPU and a Nvidia card for the PhysX? Does that work if you use the workaround or under XP?

There is no workaround for Vista, it's a WDDM driver limitation. XP shouldn't have an issue mixing GPU vendors.

Yes there is a workaround for Vista. It is in the first post within the F.A.Q. broken down in a sort of "how to" under Vista. 6th question down. Take a peek.
 
Apr 30, 2008
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Guys if ever Ati got PhysX will Ati give it to its existing 4800 series owners. i mean that is PhysX can be include as a software update or a driver update by ati later or it is a hardware thing.
 

imported_D3v

Junior Member
Aug 28, 2008
16
0
0
Has anyone tested a decent ati card with a decent nv card for physx under XP yet? I was going to do some UT3 benches with an 3870/8800gt but surely someone has already done it? If not I'll do it..
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
55
91
By all means do it! I am eager to see if it can be done. Hard or easy doesn't matter, whether it can be done successfully or not is all that matters.