SLI - Will it help?

[Sokar408]

I have my diagnostic programs running in the background that shows that my GPU is getting up to 100% usage so I know its the GPU that is bottlenecking performance, but is KSP optimized for that, or would it simply be a waste?

Here is a list of my hardware:

CPU: Intel Core i7 3770K

GPU: Nvidia GTX 670

RAM: 16 GB Corsair Vengeance

SSD: Samsung 830 250 GB

[Awaras]

It might help you if you have low framerates during launch even with a very small craft. It won't help if you get decent framerates with small craft but low framerates with huge ones, because that is limited by CPU. I still think you would get more performance if you replaced your graphics card with a single more powerful card than with SLI...

Edited July 28, 2013 by Awaras

[Sir Nahme]

with that machine no it won't help. Your limiting factor is individual clock speed on any given core

[adios_1984]

SLI will not help (in KSP). Your configuration is very similar to mine. I bet that you can run Crysis 3 with maximum details on your rig (i can on mine and i have only i5-3570k and also gtx 670). KSP is currently not optimized, hell it's still a alpha. Just wait for future optimization (maybe they will switch to another physics engine?).

[XaTriX]

Wait for optimisation, but i've the same config (z77, i7 3770k, gtx670, 32gb ram, etc) and i play it well.

Just wait for optimisation..

I'm waiting in first for multithreading

XaT

[Technical Ben]

AFAIK the GPU hits 100% utilization mainly because it does not have a FPS limiter (I think KSP is set to 120fps default). If you set the frame limiter to 60fps this might help. Generally the game is not GPU limited.

[DMagic]

The only GPU heavy aspects of the game, for me at least, are when I'm low to the surface and close to the ocean. As I understand it, the way that oceans are done in KSP can be very taxing for the GPU.

But that is rarely an issue. Small crafts aren't very hard on the GPU or the CPU, and large crafts are mostly limited by CPU speed, so it's unlikely that adding another GPU will make much of a difference.

I suppose if you play on a 120Hz monitor it could help, but I wouldn't bother otherwise.

[Sokar408]

SLI will not help (in KSP). Your configuration is very similar to mine. I bet that you can run Crysis 3 with maximum details on your rig (i can on mine and i have only i5-3570k and also gtx 670). KSP is currently not optimized, hell it's still a alpha. Just wait for future optimization (maybe they will switch to another physics engine?).

Haven't this game been in Alpha for like 2-3 years now? That was actually one of my reservations about getting it at all, as it seemed like one of those games that will never fully release, or be fully released and by no means a finished product. Don't get me wrong, I by no means regret my purchase, but it seems a bit silly that its this far into development and yet so far from do.

Anyways my problem is low FPS when dealing with large crafts, like outrageously large lifters or large space stations. I do run everything at the larges, most graphically demanding settles, MAX FPS 60, at 1600/900 windowed though.

Edited July 28, 2013 by Sokar408

[karolus10]

KSP is CPU intensive game, this mean that performance of single core of Your CPU is the main factor (You don't need really good graphics card for KSP).

[boxman]

The only thing that would help on your system would be to overclock the cpu.

[Tiron]

AFAIK the GPU hits 100% utilization mainly because it does not have a FPS limiter (I think KSP is set to 120fps default). If you set the frame limiter to 60fps this might help. Generally the game is not GPU limited.

No, it's actually because Unity's old version of PhysX (Version 2), doesn't support multicore systems. It can only run physics calculations on a single core. For that matter, I think the engine ITSELF is singlethreaded as well, and barely uses graphics acceleration at all.

Basically what happens is that each part you add requires more physics calculations to determine what it's doing (is the joint breaking, is it flexing, how's the drag affecting things, etc), and when you hit the point where that maxes out the single core the game's able to run on...in comes the physics delta time! And if you push THAT Hard enough, your FPS goes and it's a slideshow.

Given your processor, you're pretty much already as good as it gets on that score.

[blacksheep1775]

Here is a list of my hardware:

CPU: Intel Core i7 3770K

GPU: Nvidia GTX 670

RAM: 16 GB Corsair Vengeance

SSD: Samsung 830 250 GB

I think your GPU should be good, I have a GTX 550TI and it runs amazing with settings all the way up. From what I can tell almost everything you have should outperform my computer LOL. I have a Phenom II 955 3.2GHz, overclocked to 3.8, 12GB ram and definitely not an SSD.

[Basilo1146]

Because of this "Single core only" business, I'm guessing that a Tesla card would do nothing?

[Tiron]

Because of this "Single core only" business, I'm guessing that a Tesla card would do nothing?

I'm pretty sure, yeah. It's not even set up to use PhysX acceleration on normal GPUs, it will literally ONLY use the CPU and ONLY one core. The crap physics engine is the single biggest thing holding KSP back.

Unfortunately, there's no other option on Unity. Some guy was working on porting the Bullet engine as a Unity Plugin, but he was doing it by himself, and his last post on the subject is from December.

[Technical Ben]

No, it's actually because Unity's old version of PhysX (Version 2), doesn't support multicore systems. It can only run physics calculations on a single core. For that matter, I think the engine ITSELF is singlethreaded as well, and barely uses graphics acceleration at all.

Basically what happens is that each part you add requires more physics calculations to determine what it's doing (is the joint breaking, is it flexing, how's the drag affecting things, etc), and when you hit the point where that maxes out the single core the game's able to run on...in comes the physics delta time! And if you push THAT Hard enough, your FPS goes and it's a slideshow.

Given your processor, you're pretty much already as good as it gets on that score.

I said the reason the GPU is at 100% use is because of a lack of an FPS limiter. The GPU just runs at full whack for games AFAIK, it runs full speed no matter what. The CPU will reach max usage only during large part number launches. The CPU use, and limit of FPS due to that was not what I was commenting on. I was commenting on GPU usage (and GPU FPS/refreshes), not CPU usage (FPS limited by game "tick").

[GalaxyGryphon]

do you have a frame rate limiter on?

[Tiron]

I said the reason the GPU is at 100% use is because of a lack of an FPS limiter. The GPU just runs at full whack for games AFAIK, it runs full speed no matter what. The CPU will reach max usage only during large part number launches. The CPU use, and limit of FPS due to that was not what I was commenting on. I was commenting on GPU usage (and GPU FPS/refreshes), not CPU usage (FPS limited by game "tick").

Oh. Did you say GPU? I Must've missed it... well if you really wanna fix that, that's not hard. Turn Vsync on, it'll limit the framerate to your monitor's refresh rate. Most gamers tend to think of it as a bad thing, but that's only really true if you're in low framerates to start at (because it'll skip some frames it could've rendered because they would come in the middle of a monitor refresh cycle).

[rdskns4eva]

I feel your pain. I have a core i7 3770k and run dual GTX 680 SLI. I sometimes get framrate drops for some reason. I play EVE online, Bio Shock infinite, Batman Arkham City and other games and max settings with no issues, but Kerbal sometimes struggles to keep up...Not all the time but sometimes. Great game though...very addicting.

[El wonso]

Does KSP even support SLI? I have Crossfire setup and KSP uses only main GPU.

[Dichotomy]

Does KSP even support SLI? I have Crossfire setup and KSP uses only main GPU.

To a large degree it is irrelevant if KSP (or any game really) supports SLI as you can force it to do so.

Now I am not talking about just changing it to splitting the frame rendering between the GPU's through the NVidia Control Panel which will result in a marginal improvement, but rather creating an SLI profile for it using nVidiaInspector.

I have to do this with almost every game I play as a single card of mine is not enough for most games at any decent graphic setting, and the official SLI profile usually follow months after the games release.

Now as others have said KSP is more CPU limited then GPU, and your GPU usage is "probably" a sign of a lack of a frame limiter.

However if you wish to try and see if any performance gains can be had, download the nVidiaInspector, create a new profile and HOOK it to the KSP executable. Then assign the SLI DX profiles (there are two depending on whether the game is using dx9 or dx10-11) to one of the many profile INSPECTOR allows. I generally use one of the CRYSIS profiles as they tend to make the greatest use of the GPU and consequently give the greatest improvement.

Outside of nVidiaInspector you can use the second card for high level anti-aliasing calculations from within nVidiaControlPanel.

DISLCAIMER : A dedicated SLI profile created by the game DEVS (if it exists) is "usually" better then one created using nVidiaInspector, although there are exceptions (XCOM being one). Also if they ever allow for HARDWARE PhysX you will be able to dedicate one card to doing that, which "should" give a large performance boost on many systems.

Hope this helps.

[allmappedout]

Haven't this game been in Alpha for like 2-3 years now? That was actually one of my reservations about getting it at all, as it seemed like one of those games that will never fully release, or be fully released and by no means a finished product. Don't get me wrong, I by no means regret my purchase, but it seems a bit silly that its this far into development and yet so far from do.

Anyways my problem is low FPS when dealing with large crafts, like outrageously large lifters or large space stations. I do run everything at the larges, most graphically demanding settles, MAX FPS 60, at 1600/900 windowed though.

Yeah it's been in alpha a long time, but the dev team is 3 permanent staff, not exactly the hundred or so staff that an Infinity Ward or a Blizzard has available. Moreover, the dev team is made up of enthusiastic amateur programmers. By that I mean their focus has never been video games; they were originally a marketing firm who produced animations. That's not to say they're not talented as they clearly are, but it's going to have a longer development cycle than a AAA rated game because of that.

Plus, you get to play a game that constantly improves month on month, which is actually really cool when you think about it. You're getting new content to play about with for a game which cost you $20 or so. They day KSP becomes a 1.0 will actually be a mixed emotion day because being part of the alpha is part of the fun of playing KSP.

[MalfunctionM1Ke]

I am no PC Engineer allthough i have build mine myself and made it ultraquiet and still staying cool during summer when boinc is crushing the numbers.

As what I have heard the bottleneck of KSP and its Unity Engine is the CPU.

My Setup is the following

Intel Xeon E3-1230 v2 with 3.3 Ghz (3.7 Ghz Turbo) - actually a i7-3770k without the build in Graphics but a higher cache if I remember correctly.

8 GB Ram

Asus ENGTX570 DCII/2DIS/1280MD5

KSP runs fine until it come to Crafts with a huge part count.

Long story short, your only solution is to get a smaller Processor with a higher GHz-Frequency per Core, but thats is nothing to advise because KSP is not running at its full potential right now.

[Kerbocracy]

It's a bit sad that it's all CPU. I have an i7-3770k which is at factory clock (I forget what it is). I could try to overclock... But for gpu I have a gtx690, which would just love to use one of its cores for physx computations... The wasted bandwidth there just hurts... I get decent performance in KSP, but at high part counts (~1000) it gets quite laggy. So much for the massive space stations/cities I want to build. Hopefully they commit to finding a way to get gpus to carry the physics load (as they are apparently perfectly suited to that).

[El wonso]

Oh, I have just found out that Crossfire does not work in windowed mode (which I use for KSP). Anyways, running KSP fullscreen and using both GPU didn't change a thing for me. Runs as before.

[Seret]

Turn Vsync on, it'll limit the framerate to your monitor's refresh rate.

+1

Your brain can't distinguish frame rates above what you're monitor's refresh rate will be even if your monitor could display them, so you're not losing anything. 60FPS and 120FPS are indestinguishable to the human eye. Mega-FPS is about gamers' bragging rights, not any actual increase in performance.