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2 SLI'd Cards + PhysX Card?

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reap3r

Member
Joined
Jun 18, 2009
Location
BC, Canada
Hey, I was just wondering if it's possible to have 2 SLI'd cards (in my case 2 gtx 260s), and then run a third card dedicated to physx.. I've tried reading up on it but I haven't been able to get any definite answers.. i've seen some places say you can't have SLI running and enable a third card for physx, but i've also seen some people say they've pulled it off.. I'm trying to get a more definitive answer on whether or not such a setup is even possible.. I was thinking of running a GTS 250 as a physx card if possible, but i'd rather not spend the money if it isn't an option...

P.s. I'm not looking for any "well physx isn't worth it blah blah blah", i wouldn't have started this thread if i wasn't keen on spending the money on it.. :p

Thanks!
 

BobbyBubblehead

Member
Joined
Jan 29, 2009
only reason I carnt on mine is the slots are too close together.

if theres room may be the factor your picking up?

Edit: on the other hand I use a 260 for physx. but im not sure after sli theres much performance to detect :shrug: :blah:
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
Suer you can do it, but why? YOu have plenty of horsepower as is. Just leave it enabled on your SLI and dont waste your money. :)
 
OP
reap3r

reap3r

Member
Joined
Jun 18, 2009
Location
BC, Canada
Suer you can do it, but why? YOu have plenty of horsepower as is. Just leave it enabled on your SLI and dont waste your money. :)

Yeah I've decided against it actually... I will instead spend the money doing a few case mods and increasing my rig's cooling capabilities ^_^
 

amnios

Member
Joined
Dec 31, 2009
I noticed a big difference on my single gtx 280 and using a lowly 512MB 9600GT as a dedicated card. at least 30 or more frames on the maximum and at least 15 or so on the minimum... can't quite recall but I know it was double digit increases. Just believe me that I'm telling you I could see and feel the difference playing. It's not in my head.

Of course the only game I tested was Arkham Asylum but at 1920*1200 and using some AA and then even enabling full physX... I really needed that physx card.

Now, if I added a second gtx 280 I would expect that the physx card would yet again relieve some of the pressure on the two cards.

I'm not convinced that two 260's would blow that game out of the water... or more to the fact that I'm sure that adding a third physx card would increase performance as I noticed it did on my single setup. 2 260's do not super crush destroy 1 280 so I'm not going way out on a limb here I don't think. Certainly I would think that my 280 with a dedicated physx card should be nearly equal to you running jsut two 260's straight.... on batman that its. It would be very close. Go ahead, install the game and post your results on the bench and I'll do the same... with and without my physx card.

I was getting the feeling that this thread was leaning towards the idea that a physx card is useless on an SLI config. I'm not sure I agree at all.

It should be noted that I just had the 9600 GT sitting around. I might conceed to agree that buying a new card for $100 or more might not be the greatest of investments but it at least will return actual results.
 
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OP
reap3r

reap3r

Member
Joined
Jun 18, 2009
Location
BC, Canada
I noticed a big difference on my single gtx 280 and using a lowly 512MB 9600GT as a dedicated card. at least 30 or more frames on the maximum and at least 15 or so on the minimum... can't quite recall but I know it was double digit increases. Just believe me that I'm telling you I could see and feel the difference playing. It's not in my head.

Of course the only game I tested was Arkham Asylum but at 1920*1200 and using some AA and then even enabling full physX... I really needed that physx card.

Now, if I added a second gtx 280 I would expect that the physx card would yet again relieve some of the pressure on the two cards.

I'm not convinced that two 260's would blow that game out of the water... or more to the fact that I'm sure that adding a third physx card would increase performance as I noticed it did on my single setup. 2 260's do not super crush destroy 1 280 so I'm not going way out on a limb here I don't think. Certainly I would think that my 280 with a dedicated physx card should be nearly equal to you running jsut two 260's straight.... on batman that its. It would be very close. Go ahead, install the game and post your results on the bench and I'll do the same... with and without my physx card.

I was getting the feeling that this thread was leaning towards the idea that a physx card is useless on an SLI config. I'm not sure I agree at all.

It should be noted that I just had the 9600 GT sitting around. I might conceed to agree that buying a new card for $100 or more might not be the greatest of investments but it at least will return actual results.

Alright I'll do that.. I'll post back here once i get the game and we can compare.. i'm determined to lay this issue to rest once and for all :p
 

jason4207

Senior Member
Joined
Nov 26, 2005
Location
Concord, NC
I put an 8800GTS-512 in as a Physx card next to my GTX280. The only thing it did was increase heat, and force me to lower the OC on my GTX280. My games still played the same...locked at 60fps w/ vsync at 1920x1200. I even tried Mirror's Edge, but I was still getting 60fps lock w/ only the GTX280. In Crysis it reduced my framerates when I had the extra card in there.

I moved the 8800GTS-512 to my HTPC, and now I have a whole other PC that can game hard.

There may be some benefit to using a dedicated Physx card, but if you're over the refresh rate of your monitor it doesn't really matter anyway.
 

amnios

Member
Joined
Dec 31, 2009
Crysis does not have any physx. Did you expect to see fps increases or were you simply instead pointing out that an active dedicated physx card lowers overall performance in non physx games(or just crysis)? I'm curious.

But Mirror's Edge... if you have res settings and AA maxed and have physx on screen with heavy enemie count.. I wonder if you'd still get 60fps. My guess is that you may see 60fps on light screen activity but not 60fps on the minimum side during heavy on screen action. Physx card should bring the minimum up.

Can you confirm this?

PS... increase of heat I could agree with. The physx card could kinda block the nice intake fan of the 280 to a point... is that what your attributing your heat increase too?
 

jason4207

Senior Member
Joined
Nov 26, 2005
Location
Concord, NC
Crysis does not have any physx. Did you expect to see fps increases or were you simply instead pointing out that an active dedicated physx card lowers overall performance in non physx games(or just crysis)? I'm curious.

My point is that the only game that really taxes my system sees no benefit from the extra card.

But Mirror's Edge... if you have res settings and AA maxed and have physx on screen with heavy enemie count.. I wonder if you'd still get 60fps. My guess is that you may see 60fps on light screen activity but not 60fps on the minimum side during heavy on screen action. Physx card should bring the minimum up.

I ran AA at 2x. At 1920x1200 you really don't need that much AA if any at all. All other settings are maxed, though. I only played the game for a few days so keeping the extra card in there didn't make a lot of sense for me. That extra card can do a lot more work in another PC.


PS... increase of heat I could agree with. The physx card could kinda block the nice intake fan of the 280 to a point... is that what your attributing your heat increase too?

No, the cards had plenty of space between them; the 2 PCIe slots are spread out on my board. The extra card draws more power thus putting additional strain and heat on the PSU and mobo. It also heats up the inside of the case more (it doesn't all go out the back). And the heat coming off the back of the 8800GTS PCB board will rise and be drawn directly into the intake fan on the GTX280 even if they aren't sandwiched together.

I had to reduce my GTX280 OC to remain stable.

My overall point is that I tried it and didn't notice any improvement. My PC is under my desk next to my legs and I could feel the additional heat being pumped out. In the summer time I can definitely do w/o that. Fell free to give it a whirl, but also be prepared to be disappointed. I pride myself on a quiet, cool running, powerful, yet efficient rig, and the overhead of an additional card for marginal gains in only a few situations doesn't work for me.
 

amnios

Member
Joined
Dec 31, 2009
very curious why you did not see the increase in performance as we all did.

My system....

i7 lapped 920 3.6 GHz with NOC SE cooler
6 GB 1333 RAM TRI CHANNEL
BFG GTX 280 OC overclocked to similar settings to yours
9600GT 512MB physx
Asus Rampage 2 extreme
Corsair 1000W modular power
NZXT Tempest
Case Side Remains Open

No doubt my system is a bit more powerful and likely cools better.. but even if I throttle back my cpu and close up the case... I'm still going to see FPS increases on the min and max.... yes I might have to throttle back my GTX OC as well.

But still even then I will see FPS increases.

Curious.

Can anyone else share their experience that Physx cards do NOT help performance on physx games?

Very curious.

(PS... I agree however that for the most part your GTS is better used in the other computer... nice projector btw on that system)
 
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jason4207

Senior Member
Joined
Nov 26, 2005
Location
Concord, NC
You've got more CPU crunch power, but I seriously doubt your games run any faster. And that i7 runs a lot hotter than this cherry Q9550; I can guarantee that. I get better directional airflow with my case side on, and it's quieter that way; plus I have a huge door fan. I've got high-powered Delta and Panaflo fans all over my case w/ a Sunbeam Rheobus fan controller to keep them quiet. This thing can really move some air if I crank them wide open (~300CFM in and ~230CFM out)!

(2) 120mmx25mm 95 CFM Delta's in front (intake)
(1) 250mm 800rpm 105 CFM fan on the side door (upgraded from stock 600rpm fan) (intake)
(1) 120mmx38mm 115 CFM Panaflo in the back externally w/ grill cut out (exhaust)
(1) 92mmx25mm 58 CFM Panaflo in the back mounted externally w/ grill cut-out (exhaust)
(1) 92mmx25mm 58 CFM Panaflo on top mounted externally w/ grill cut out (exhaust)
(1) 120mmx38mm 130 CFM Delta Tri-blade on the TRUE (CPU)
(3) 92mm fans on the Arctic Cooling Accelero XTREME GTX280 (GPU)
(2) 70mm fans in a PCI-slot fan cooler to help cool the back side of my gfx card
(1) 80mm fan on RAM

I'm not saying the extra card for Physx doesn't help. I'm saying it doesn't make any difference if you're framerates are already beyond the refresh rate of your monitor. If going from 2xAA to 8xAA in 1 or 2 Physx games at 1920x1200 (where extra AA is going to be VERY hard to see) is worth the overhead to you then go for it. It wasn't worth it for me.
 
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amnios

Member
Joined
Dec 31, 2009
Batman Benches...

GTX 280, no dedicated physxcard, no vsync

1920x1200, all maxed, physx high, 2x AA = 24 min, 64 max, 45 average fps
1920x1200, all maxed, physx high, 8x AA = 22 min, 54 max, 40 average fps



GTX 280, 9600GT dedicated physxcard, no vsync

1920x1200, all maxed, physx high, 2x AA = 39 min, 106 max, 72 average fps
1920x1200, all maxed, physx high, 8x AA = 38 min, 91 max, 64 average fps


On my 26" LCD I can spot the difference in image quality from 2x to 8x by the way.

Looks like the 9600GT gave me about 15-16 fps better on the min and about 37 - 42 fps on the max... and about 24 - 27 fps on the average.

CPU temps did not fluctuate at all during any of the testing... maxed out a 60'C
GTX280 temperature differences were not noticeable.

For me, cooling is not a factor.... LOVE THE PHYSX CARD!

I do use vsync on my games by the way... I just disabled it so you could see the potential max framerates if I was not using an LCD... again, physx card gave about 40 fps increase on the max!
 

jason4207

Senior Member
Joined
Nov 26, 2005
Location
Concord, NC
Like I said...1 or 2 games.

Batman and Mirror's Edge.

I have the Batman demo, but not the full game. Is there anyway for me to run some comparisons? How did you do your comparison's? Is there a built-in benchmark?
 

amnios

Member
Joined
Dec 31, 2009
I'm sure I'll come across other physx games.

Full version has a benchmark on the main menu