SLI benefit?

[seikdel]

Hey Folks. I'm running an i5 (3.6GHz, I think? Can't remember for certain ATM) with a GTX 570 2.5GB. I've never run SLI before, and I'm wondering if it's worth the money and PSU drain to toss a second card in. I'm aware of the limiting nature of VRAM, but I figure 2.5GB is decent for the time being.

Oh, and I've got 16GB of DDR3 (1600? Again, I think that's what it's at...) and one 1080p monitor.

 

Basic question: How much do you think I would benefit from a 2nd card in SLI at this point? How long do you think I could get by on that setup before needing to upgrade?

 

And yes, this is subjective. I'm looking for other folks' experiences with SLI and get a feel for how much benefit they've had.

[HiJack]

No support for SLI and very little frame gain in DCS as far as I know. Do a search in this forum and I think you will find a lot of discussions with SLI in it.

[westr]

Hi, I recently built a new pc, put an i7 processor in, have 16gbs of Ram, and I bought two Radeon HD 770 graphics Cards, overall I have been a little dissapointed with my machines performance in DCS world. And I have been playing with my specs for a long time now to tweek its performance. Don't get me wrong I am able to have pretty high settings and manage to average at least 20fps in most circumstances and its playable but there are some occasions when (and its mainly flying near or taxing round an airbase with some static aircraft) that my fps drop to 11-12 and I still get some stutters. I can see as well in my Catalyst control centre that both graphics cards are running. My advice would be no, save yourself the bother if you only play DCS simulations, I don't think you get any better performance than if you had just the one card. And its not cheap I spent a lot of money on my two cards, and they improve all the time so I would hold on, I hear that if DCS release their new EDGE engine it could utilise SLi/ crossfire better. By which time I will need to buy another two cards as mine will probably be dated by then, I'm sure you understand what I mean, hope this helps...

[Valinor]

Most games don't use SLI/Crossfire properly anyway, i would never go for two gpus to be honest.

[TZeer]

SLI works fine. Crossfire don't. Crossfire has issues getting both cards to work at 100%.

 

I have used 2x 580 GTX in SLI myself. As long as your CPU is not holding you back your cards will be taxed to 100% on both cards. But you wil most likely run with VSYNC on and you will be able to run the game at 60 FPS.

 

As long as the CPU is not holding you back.

 

Is your GPU working at 100% now? Are you running with VSYNC on? Are you able to get 60 FPS now? If not, what is holding it back? CPU or GPU?

 

If you use a program like nvidia inspector and monitor your GPU usage during FPS drop, you can determine if it's the lack of GPU power or CPU power that's causing the drop.

 

If you loose FPS and the GPU usage is going down, it's your CPU that is the reason. If you loose FPS and the GPU is working at 100%, it's the lack of GPU power.

[westr]

I have a few flight sims, IL2 COD I noticed no improvement at all using crossfire, but I have given up with trying to improve the performance of that sim. But FSX I noticed a notable improvement in performance but that's about it as far as sims are concerned.

[aap_flanker]

Better build a raid 0 with 2 SSD....

Just my cents...

[seikdel]

Flanker: I can run DCS off a ramdisk if I really want to eliminate load times, but thanks for the tip =)

[aap_flanker]

Flanker: I can run DCS off a ramdisk if I really want to eliminate load times, but thanks for the tip =)

 

It's not only the load time... You will notice a whole performance increase... Just try

[112th_Rossi]

I think there is a bit of a hard limit as to the maximum amount of FPS this sim can push out. I think we just need to wait for EDGE before we see significant FPS improvements across the board.

[TZeer]

There is no hard-limit. DCS can push out 200+ fps if you have the hardware.

 

You can set up a single unit in the editor in a remote location if you wanna test.

 

 

And to repeat myself, SLI works good as long as other components dont hold you back.

[gavagai]

2 video cards is a roll of the dice. You are almost always better off upgrading to a better card, unless you find a very nice deal on a second one.

 

The performance improvement is not linear, and most games do not officially support it. Why some people jump for 2 gpus at the first chance is a mystery to me.

[westr]

Don't know how many people have ATi cards and Crossfire enabled, not many by the sounds of things. But I have discovered that after enabling Crossfire in my catalyst control centre. Then creating a profile for DCS World and pretty much putting all your settings to use application settings. However under your crossfire settings switch to AFR Friendly. Then I downloaded RadeonPro. Creating a DCS profile with that to with the same directory path, and under the tweeks tab under crossfire X tweeks I set it to Alternate Frame Rendering. Not only did it eliminate the flickering clouds that I know some people have posted about on the forums but I experienced a significant boost in FPS over anything I have had previously. May not work for everybody but it has worked for me I hope that it helps somebody....

[Headspace]

There will be a point at which your CPU becomes the bottleneck, and at that point no additional GPU will help you.

 

IMHO, the only reason to do SLI is if you want to use multiple monitors and still get competitive framerates. If that isn't your goal, then SLI will be of marginal benefit to you, even with a modern CPU.

[pezman]

It's not only the load time... You will notice a whole performance increase... Just try

 

He's right.

 

The one thing I would tell anyone to get for this game is an SSD. There are too many textures that the game needs to load for a regular HDD setup, gotta have an SSD, that is unless you want to play the game on the lowest settings.

[Quirkitized]

As Tzeer has stated, it works, and it works well enough to justify it, I think, even for single monitors. Do not expect 80-100% scaling like high profile games though.

 

http://forums.eagle.ru/showthread.php?t=99637

[BRooDJeRo]

+1 on the fact that CPU is the main bottleneck in DCS performance and an SSD additionaly (SSD improves any game). When you use multicores make sure that a single core has a decent clockspeed. You only use 2 of them, the rest is just being fancy in the background.

[MadTommy]

IMHO, the only reason to do SLI is if you want to use multiple monitors and still get competitive framerates. If that isn't your goal, then SLI will be of marginal benefit to you, even with a modern CPU.

 

^^ This.

[SimHog]

Don't know how many people have ATi cards and Crossfire enabled, not many by the sounds of things. But I have discovered that after enabling Crossfire in my catalyst control centre. Then creating a profile for DCS World and pretty much putting all your settings to use application settings. However under your crossfire settings switch to AFR Friendly. Then I downloaded RadeonPro. Creating a DCS profile with that to with the same directory path, and under the tweeks tab under crossfire X tweeks I set it to Alternate Frame Rendering. Not only did it eliminate the flickering clouds that I know some people have posted about on the forums but I experienced a significant boost in FPS over anything I have had previously. May not work for everybody but it has worked for me I hope that it helps somebody....

 

You are a life saver my friend. I'm so stoked!!!

 

I played around with RadeonPro like you've described. I found that setting the XFire slider to Supertile gave me the best results.

 

I'm now getting much higher FPS than before. Haven't done extensive testing but I've noticed an average of 40 to 60 FPS, it still dips when there is a lot of smoke but nothing like before, min I've seen is 25 and both my GPUs are averaging 80% usage. :thumbup:

[Wayc00lio]

I've been toying with getting another GTX680 sometime in the not too distant future. But currently I'm getting 60 FPS all maxed out anyway so what benifit would I see? Not much probably, not noticable anyhow.

[SimHog]

I was getting OK frames when I disabled XFire, but not great, but with the resolution I run and having a 2nd GPU I was tearing my hair out trying to get to work right.

 

I gave up back in Dec but after seeing this thread and seeing there was a new patch I'd thought I'd give it another go ... I couldn't be happier with how DCS is running now. :pilotfly:

[Slayer]

I've had SLI setups in every generation of Nvidia except the 600 series and now the Titan. It's always mixed results and days of tweaking to get it working ok.

 

Flight sims all in all don't run great with SLI: IL-2, FSX, X-plane etc..but like I said you can tweak and may find success. If you play other mainstream games as well as sims it is still worth the investment but if you only play sims I would say invest in some other piece of hardware like good rudder peddals, SSD, TrackIR, butt kicker or a new stick.

 

I will say that things on the DCS side have improved in recent years but it's still not directly supported still.

 

A limitation often overlooked is video memory ~ by going SLI you don't effectively double your video memory - each card is rendering 1 frame ( or parts of it depending on the mode) very important when moving to larger displays or multimonitor setups. So using 2 elcheapo 1GB cards you still only have 1GB available to render with.

 

Lots of people make the mistake thinking they can buy a lowend card then later go with SLi and it will be better than an highend card. Not so. If this is the case just hold out and buy the fastest card with the most memory at a later time and save your money....

 

Edit: not to mention the cost of upgrading to a high quality PSU that supports SLI ~ these can be pricey and if you cut corners it will come back to haunt you....unstable and can't figure out why, burn't cards or worse yet burnt MB and cards.

Edited April 18, 2013 by Slayer

[westr]

Interesting that you got supertile to work CoderX71, do you know what settings you have in your Catalyst control centre when you set radeonpro to supertile?, I may have to have a play around with that as well, glad it has worked for you!

[swissross]

I've got 2 Nvidia GTX 285's in SLI. Fired up the game the other day and was only getting about 30FPS. Checked my settings and SLI was disabled. EVGA Precision was also only showing one GPU being utilized. Enabled SLI, restarted the game, and in the exact same mission I was getting 60 FPS. So yes, SLI does make a difference in this game. Maybe it's less noticeable with newer cards, but with my generation of cards it makes a big difference. Both of my GPU's are nearly pegged during game play.

 

Here's a couple screen caps to show the difference...

 

Single - EVGA precision shows GPU 1 maxed out, GPU2 isn't being touched. FPS is at 31

https://dl.dropboxusercontent.com/u/8575186/single.jpg

 

SLI - Both GPU's maxed out. FPS is 57

https://dl.dropboxusercontent.com/u/8575186/SLI.jpg

 

On my system at least, the graphics card is holding me back. As you can see, the CPU isn't being thrashed at all.

 

And interestingly enough, it seems that SLI enabled or not, both cards are utilizing nearly all of their ram. Just noticed that. As I sit here typing this They are only using about 150MB. But in each configuration during game play they are nearly maxed out.

Edited April 18, 2013 by swissross

[locoidal]

You are a life saver my friend. I'm so stoked!!!

 

I played around with RadeonPro like you've described. I found that setting the XFire slider to Supertile gave me the best results.

 

I'm now getting much higher FPS than before. Haven't done extensive testing but I've noticed an average of 40 to 60 FPS, it still dips when there is a lot of smoke but nothing like before, min I've seen is 25 and both my GPUs are averaging 80% usage. :thumbup:

 

I was getting OK frames when I disabled XFire, but not great, but with the resolution I run and having a 2nd GPU I was tearing my hair out trying to get to work right.

 

I gave up back in Dec but after seeing this thread and seeing there was a new patch I'd thought I'd give it another go ... I couldn't be happier with how DCS is running now. :pilotfly:

 

Hi,

How did you do that??

 

If I set Crossfire ON and using default parameters --> 20 FPS drops (from 45 to 22) and stuttering.

If I set Crossfire On and AFR in whatever (or both) CCC and Radeonpro ... I get the flickering clouds.

With supertile i get al textures in red/yellow/black colors...

So... how did you do taht ? .. can you explain the procedure to get these results?

 

Thx in advance.