SLI or dedicated PhysX?

[josephlear]

Hello,

I get the basics of physx and sli/crossfire. What do you guys think would be better for BFBC2... two GTX 460 1gbs in SLI, or make one dedicated physx? I've heard 460's don't get much of a performance boost.

 

[skolpo]

You don't need such a high-end card for physx. Honestly, you don't need a dedicated card for physx period. Physx only works on a select number of games and of those select few, only three or four actually utilize physx well (Batman: AA, Mirror's Edge, etc). Don't emphasize too much on physx, if at all. SLI a pair of GTX 460s if you know the rest of your computer can handle it.

 

[wolfram23]

SLI the 460s for sure. Like skolpo said, a 460 is way overkill for PhysX. At most you'd need a 250... I've had zero problems with a GT 240 for PhysX and that's on a 4x PCIe lane (the card was $65 after MIB).

Anyway, yeah, SLI the 460s and they can handle the PhysX too.

Also, BFBC2 doesn't use GPU accelerated PhysX. The one's I've played with GPU PhysX are Batman AA, Mirror's Edge, Dark Void, Mafia 2, Cryostasis, and Metro 2033.

 

[jyjjy]

Yes, SLI obviously as the game does not use Physx of any sort.

 

[josephlear]

Oh really? I thought it did, anyway ultimately I'm looking forward to Battlefield 3, which they say will rely on physx, but it sounds like so matter how you slice it SLI-ing the 460's is the way to go. Thanks for the input!

 

[mindless728]

Oh really? I thought it did, anyway ultimately I'm looking forward to Battlefield 3, which they say will rely on physx, but it sounds like so matter how you slice it SLI-ing the 460's is the way to go. Thanks for the input!

nope, BF3 will run on the Frostbite 2 engine (BF:BC2 uses 1.5), so no PhysX on that either

 

[jyjjy]

Who is they? Are you confusing DX11 with Physx or something?

 

[Helltech]

I'm pretty sure you would be better off using SLI instead of a dedicated Phsyx card regardless of it BF3 used physx or not. I have SLI GTX 260's and I can turn Phsyx up all the way and I don't have problems (this includes Metro 2033 and Mafia II).

 

[g00fysmiley]

yea imo dedicated physix for most games is more like... well i upgraded to another nvidia card and instead of throwing this card out I'll use it for that >_< i guess some people get off on tesselation and physics but give me smooth fps 30+ and i'm happy if the glass doesn't pounce off the ground properly when shot and the pieces fall

 

[17seconds]

SLI will nearly double your framerates, and enabling PhysX will only cost you a few frames per second. So overall, you will get both PhysX and much better performance from the SLI vs dedicated PhysX setup.

If you follow my drift:
SLI - PhysX = 196%
Single card + PhysX card = 104%
(single card = 100%, double card =200%, PhysX benefit/cost = +/-4%)

 

[jyjjy]

I do believe you just entirely made those numbers up.

 

[notty22]

The thing is , if you own two 460's, you can play with nvidia control panel and test these things out. You can have your sli connector on, and just change settings. Turn off sli, dedicate card 'b' for physX and run Mafia II's benchmark.
IMO, its going to be a rare case that sli and auto gpu physX is not your best setting.

 

[spentshells]

I do believe you just entirely made those numbers up.

+1

 

[ggman]

I would also suggest that you test Mafia II in SLi and 1 x 460 + Physics but im willing to bet that the SLI will win by a sizable margin

 

[17seconds]

I do believe you just entirely made those numbers up.

You got me there.

For the sake of accuracy, I went to look it up:

Mafia 2: 1 GTX460 + 1 GTX275 PhysX card = ~+25% versus single GTX460
http://www.bit-tech.net/hardware/graphics/2010/09/03/mafia-2-physx-performance/2

GTX460 SLI performance = ~+200% versus single GTX 460
http://www.guru3d.com/article/geforce-gtx-460-sli-review/

My revised equation:

SLI - PhysX = 175%
Single card + PhysX card = 125%
(Single card = 100%, SLI = 200%, PhysX benefit/cost = +/-25%)

Wow, I actually didn't realize a dedicated PhysX card made that much difference, but it still won't beat an SLI setup.

 

[spentshells]

ok I was seeing that as a blanket statement which it certainly looked like
excellent #'s though if you are playing that game in particular

 

[17seconds]

Battlefield Bad Company 2 uses the Havok engine to render CPU based physics. Havok was also used in Oblivion to enable the player to pick things up and throw them around.

 

[jerreece]

I would most definitely vote for GTX 460 SLI. I don't think it really matters what you play, a GOOD SLI setup will outperform a good/decent single card plus a dedicated PhysX in most situations I'd be thinking.

nVidia's SLI scales pretty darn well these days, reaching something like +90% performance gains in many cases.

Also, as was previously stated, Bad Company 2 does not use PhysX. So a PhysX card is useless there. Now, you CAN use a PhysX card with Mafia II however. But you'd still probably be better off with GTX 460 SLI than a dedicated PhysX card in that situation I'd think.

 

[nforce4max]

Phsyx is like intel itanium both have limited support and limited use so it shouldn't be a priority unless there is money to burn. I suggest that you go sli and just enjoy the fps. For most 4:3 and 16:9 ress it will be op while surround forget it.

 

[jyjjy]

GTX460 SLI performance = ~+200% versus single GTX 460
http://www.guru3d.com/article/geforce-gtx-460-sli-review/

SlI scales well but it certainly is not 100% on average, even in the very article you link. Here is a handy chart for 1080p from a different article. The light green bars are the scaling in each game;

http://www.xbitlabs.com/articles/video/display/gf-gtx460-sli_12.html
Note the only GPU accelerated Physx game on there is Metro 2033 and it scales at 63%.
Physx also has varying performance penalties depending on the game, what card is being used and, in the case of Mafia 2 specifically, what setting is being used.