Lets get scientific about SLI/Crossfire

[Pilotasso]

I read lots of past threads about this subject, but I have found some contradicting posts and it is not clear to me whatever SLI/crossfire will bring any benifit to LO.

 

Some say it does increase FPS while others say they saw no such thing at all, and the SIm is CPu bound, thats a fact.

 

So I would like to urge those who have dual setups, for the sake of those who are researching, what differences you got by disabling one card as oposed to the 2.

 

Would you be kind enough to post your findings? :)

[Pilotasso]

Falcon is a decade old... you can do whatever with it with just about any mainstream CPU... :huh:

[Kuky]

I don't get microstutters (these are not low FPS as some may think, quite the oposite... happens only when my framerate gets to 60 FPS - which is my monitor set refresh rate) in LockOn when I disable Catalyst AI (which they say disables CF). I think single GPU setup is better as you don't get issues related to SLI and CF.

[Pilotasso]

You got 2 cards? what happens to FPS when you disable one of them?

[G3]

this is a good idea, maybe you can decide on a particular track or something to create an even playing field.

like quick start f-15 mission, take an initial reading as it starts and then drop to 1000 feet, just an idea.

 

resolution, graphics settings, AA and AF and system config can all have a big effect on things.

 

eg: a guy with a single 19" monitor might not see any gains with sli,

but a th2go for instance could be another story altogether.

 

my point is,

for those kind enough to respond

it might be worth mentioning things like:

 

cpu

videocards model and driver version

in game resolution

in game graphic settings

altitude at the time, over cities etc.

 

 

starting the F-15 quickstart mission / then diving to 1000'

 

in sli: 117/80-90 fps

 

non sli: 129/80-90 fps

 

that seems weird to me, hmmm?

Edited August 5, 2008 by G3

[Kuky]

Here's a definite conclusion on my end regarding LockOn and CF/SLI setup:

 

Get as fast CPU as you can!!! ;)

 

CF OFF

46-47 FPS flying over Overcast (8xAA 16xAF)

 

CF ON

99-100 FPS flying over Overcast (8xAA 16xAF)

 

This is one situation where CPU is not a factor at all (obviously) and as shown CF does work with LockOn... now the sad part... I ran one track I recorded while flying A-10 online for 5 minutes, framerate recorded with Fraps:

 

CF OFF

Min:25 Max:82 Avg:41

 

CF ON

Min:24 Max:101 Avg:42

 

Now, wether or not you want to get CF/SLI for Lockon it's up to each individual but for me seems unless you're flying over Overcast and have really high resolution and absolute max amount of AA and AF I really see no much benefit from it... most definitely CPU is what you should be concentrating on and gameplay only gets bad with MIN FPS and not MAX, and as from this quick test AVERAGE framerate is very much the same. One reason not to go CF/SLI are likely issues with drivers and things like microstutters which I am experiencing on occasions (but enough to kill my mood when flying when it does happen)

 

PS: This was run with 4GHz E8500 CPU and 2x HD4870 in CF on Windows XP pro SP3

Edited August 5, 2008 by Kuky

[Pilotasso]

Any more ginnea pigs? we can use some more :D

[Pilotasso]

I have been conducting experiments with my machine. On the 169 server my FPS doesnt change at all when the rendered objects vary between 200-1000. Jumping from a 19" to a 22" screen size resulted in a definate FPS drop.

 

I ran supreme comander Benchmark, with 2.66 and 3 GHZ configs. Min FPS changed from 15 to 16 and max from 67 to 74, average from 39 to 40.

 

At 3 GHz my basic config is almost the exact same tested on tomshardware for the radeon 4870 review .

 

http://www.tomshardware.co.uk/radeon-hd-4870,review-31046-11.html

 

Comparing these results to the 9800Gx2, they get 74 FPS average. Almost double what I got now.

 

Being the game CPU bound I am lead to beleive the game is tied more on CPU architecture than MHz. Hence I would not benifit much from aquiring a faster C2D CPU but would infact get a bigger FPS jump by using a better GFX right now.

 

Your opinions?

Edited August 9, 2008 by Pilotasso