choosing a physx card for hybrid with crossfire

jojo69

jojo69

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One of the main reasons I built my box was to do rendering and bugtesting for my good friend's project http://www.ecstasymotion.com/

It turns out that his program is a bit heavier in its use of physx than I had expected. I went for 2@HD6950 when it was time to pull the trigger, the value with the unlockable shader cores won me over. I am quite happy with the performance of the cards, but I want this thing to absolutely crush his app so I am looking at adding a dedicated physx card.

I am running the Rampage Formula MOBO, so the only slot for the card will be between 2 aircooled 6950s. I have been looking for a short card that will not interfere with the #0 cards intake air. It seems like this Galaxy GTX550 http://www.newegg.com/Product/Product.aspx?Item=N82E16814162078 would fit the bill pretty well.

Is a GTX 550 for dedicated physx stupid overkill?

Do folks have any suggestions on appropriate older cards I might keep an eye out for used? Specs would be 7.5" long or less, single slot or slot+ cooling solution, plenty of power to crush physx without paying for capacity and power consumption I don't need.
 
Physics calculations scale pretty linearly - the better your card, the better your results. Pretty much without limit at this point.

Check out HD5770 bottlenecked by 9800GT for PhysX. The HD5770 did 125fps without PhysX. Even with a GTX285 dedicated to PhysX, it still slowed it down to 82fps. With my HD5870, it dropped from 217fps to 107fps with the GTX285. The GTX285 is one notch higher than the GTX550 on Tom's chart. The GTX260 is in the same bracket as the GTX550, and that was the minimum I was recommending a year ago for specifically purchasing a PhysX card.

The GTX550 will definitely not be too much, in terms of pure processing power. It's going to come down to how much you want to spend relative to how much you're gaining.
 
OK, thank you, good information.

My other concern of course is keeping clear of the other cards' airway...that 550 was the most powerful current production card I could find in a short, single slot+ form factor. Everything more powerful was in full blown double slot packages...well, there was one single slot but it was a foot long. edit here it is http://www.newegg.com/Product/Product.aspx?Item=N82E16814162072 Galaxy GTX460...too long

That is why I am hoping there is something no longer in production that might fit the bill that I can pick up used...
 
What games do you have that justify the purchase of even buying a physx card?
If you play them online pretty sure you won't even see the fanciness anyways.
 
SpongeBob said:
What games do you have that justify the purchase of even buying a physx card?
If you play them online pretty sure you won't even see the fanciness anyways.
Click to expand...

not games...well I game also, but the purpose of the box is stress testing the awesome animation application linked in the OP.

Check it out.
 
jojo69 said:
Well Spooony,

I am not a code genius, I am good at hooking up wires and hoses, but re the X87 instruction set my understanding is that it would depend if an Nvidia GPU (and in the case of stock drivers ONLY Nvidia GPU) is present or not.

http://www.realworldtech.com/page.cfm?ArticleID=RWT070510142143

tldr version...ask Nvidia
Click to expand...

nope read this.
http://techreport.com/discussions.x/19216

A cpu is awful in reading X87 instructions that's why they can claim a gpu is so much faster. When something uses physx and its got a nvidia patch on it then your cpu is going to do that X87 instructions if you don't have a nvidia card which can drop your performance to crawling speed. If it was in X86 then the cpu couldve done it with SSE way faster. Intel proved it with quick sync.
 
InvisiBill said:
Physics calculations scale pretty linearly - the better your card, the better your results. Pretty much without limit at this point.

Check out HD5770 bottlenecked by 9800GT for PhysX. The HD5770 did 125fps without PhysX. Even with a GTX285 dedicated to PhysX, it still slowed it down to 82fps. With my HD5870, it dropped from 217fps to 107fps with the GTX285. The GTX285 is one notch higher than the GTX550 on Tom's chart. The GTX260 is in the same bracket as the GTX550, and that was the minimum I was recommending a year ago for specifically purchasing a PhysX card.

The GTX550 will definitely not be too much, in terms of pure processing power. It's going to come down to how much you want to spend relative to how much you're gaining.
Click to expand...
The drop in framerate isn't entirely due to a PhysX card bottleneck

When you enable hardware accelerated physics, you're also asking the graphics card to render a lot of new objects that it didn't have to when hardware accelerated physics was disabled. Rendering more objects = lower framerate, regardless of which dedicated PhysX card you use.
 
Spooony,

I'm pretty sure that is exactly what the link I posted is saying.

Everybody knows Nvidia gimped PhysX for CPUs by neglecting multi threading and SSE...ancient history, that is not the issue here.

I am just looking for the best card for my situation.
 
jojo69 said:
Spooony,

I'm pretty sure that is exactly what the link I posted is saying.

Everybody knows Nvidia gimped PhysX for CPUs by neglecting multi threading and SSE...ancient history, that is not the issue here.

I am just looking for the best card for my situation.
Click to expand...

just trying to make sure whatever your using takes advantage of physx. Its your money after all I won't recommend anything without proper info, Coz if a what if happens your the one going to dissatisfied for wasting your money not me. So forgive me for just making certain its actually a physx problem (which is X87) or maybe a ported X86 cuda problem .
 
Unknown-One said:
The drop in framerate isn't entirely due to a PhysX card bottleneck

When you enable hardware accelerated physics, you're also asking the graphics card to render a lot of new objects that it didn't have to when hardware accelerated physics was disabled. Rendering more objects = lower framerate, regardless of which dedicated PhysX card you use.
Click to expand...

Right, but there was a repeatable improvement going from a GTX275 to a GTX285, even with only the HD5770 for graphics. In this case, using a GTX275 dedicated to PhysX was still bottlenecking the HD5770's graphics. If I could've tested with something higher than a GTX285, I'm guessing it still would've been the bottleneck.
 
InvisiBill said:
Right, but there was a repeatable improvement going from a GTX275 to a GTX285, even with only the HD5770 for graphics. In this case, using a GTX275 dedicated to PhysX was still bottlenecking the HD5770's graphics. If I could've tested with something higher than a GTX285, I'm guessing it still would've been the bottleneck.
Click to expand...
Even though there was an improvement when you used a faster PhysX card, the PhysX card isn't the main bottleneck according to your benchmarks.

Compare your 5770 numbers to your 5870 numbers, the minimum framerate shoots WAY up with the faster dedicated graphics card, even when using the same PhysX card.

If the PhysX card were actually bottlenecking the 5770 (forcing the 5770 to wait for the PhysX card) then the minimum framerates observed on both the 5770 and the 5870 should have stayed roughly the same when you swapped in a faster dedicated graphics card. Your minimum framerate more than doubled, meaning the same PhysX card was more than capable of keeping up even at twice the framerate the 5770 could muster.

Look across the minimum framerates recorded on the 5870 as well. It's always about 63FPS no matter what PhysX card you used, which looks to me like the PhysX card was waiting on the graphics card, no the other way around.
 
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I just got 6970's I'm putting into crossfire.

Would a 460GTX be able to be used for physics with them without affecting the performance too much. (I'm assuming hacked drivers would have to be used).
 
bump...

I just want to know what the most powerful card is that I can cram between two air cooled 6950s

sorry I've been absent from my own thread...got banned for a week
 
The 460 768MB would be a fantastic card for the price, it's at 900 GFLOPS stock, one notch below the 285. though I'm not sure how good its performance is in PhysX exactly.
 
Would a 480GTX work with a 6990 for physx? I'm asking because i have a surplus 480 and if i can use it for something besides a paperweight i'll try to do it... :)
(May sell it tho)
 
Pretty sure yeah

you have to run the driver hack for the Nvidia card..google "hybrid physx"

I have not done it myself yet...but lots of people have, I don't see why those particular card choices would pose a problem.
 
bumping y'all in your subscribed threads...sorry

plugged a GTX 285 in my sig sys...recognized but no folding or PhysX

WTF?

got 285.27 NV

got 9.11.0621PhysX

got hybrid hack 1.04

???
 
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