Call of Duty 4 Performace. A little something for you to try.

[DarKStar]

Originally Posted by SKYMTL

What I am saying is that using a SINGLE CARD while using the ENABLE DUAL GPU option will INCREASE YOUR FRAME RATES EVEN IF YOU ONLY HAVE ONE CARD INSTALLED.

Can anybody here reproduce this on an NVIDIA card ? I would like to but have little to no time.

Are you sure that the IQ remains the same, that no feature is removed because I don't see why it would increase frame rate - I was confusing with another thread about enabling threading optimization, but your function has nothing to do - I'm wondering if perhaps the settings are reversed or it's a mistake in the drivers and should be the other way around - can you run the same test again and check your CPU usage are they the same ?

[MpG]

Interesting little phenomenon.

Just ran through the "Blackout" mission a few times on my own setup. 16x10, all settings maxed. No timedemo, just freeform, although by this point, I run the mission pretty consistently. Ran twice through without enabled, and twice with.

Without Dual GPU enabled, I was getting a min/max/avg of 55/399/124; with Dual GPU, 57/300/118. Nothing there suggests any meaningful variance. If anything, this would point towards the issue being an ATI one.

On the other hand, I ran Dual GPU enabled first. After running through twice, then immediately switching Dual GPU off, I almost immediately got the distinct impression that the IQ had improved slightly. Very strange, very seat-of-the-pants, but the "feeling" was definitely there. Not sure what to think of that, tbh.

[SKYMTL]

I'll have to do a bit more testing but it seems like Cadaveca could be onto something here.

[DarKStar]

You should post those findings on the guru3d forum in the Drivers section they have drivers fanatics there I'm sure someone might explain this - I know for a fact that no graphics card driver makes FULL use of your GPU, there is always room for improvements, and it's a shame that hardware companies make good hardware but their software does not take full advantage of it - and there are quite a few non documented features you can enable using those drivers i'm sure.

[cadaveca]

IT's not the drivers...and I'll explain why SKYMTL follows along with me...

Take G80. 128 threads/pipelines? R600/R670 is 320...

So, G80 does more complex math, and benefits from longer calculations. R600 excels at many calculations at one, but those tasks are limited.

Wnable SLi/Crossfire, and if your engine isn't aware of more processing ability, the gains from an extra GPU aren't going to be very large...purely based on info from one frame is almost always needed for the next, and the associated delays involved in syncing that data...

But COD4...well, it creates more threads in dual gpu mode, as does pretty much any game that offers such functionality. COD4 is designed to run well on mid-range/last-gen hardware, and as such, the actual rendering tasks are small, but numerous calculations. Enabling dual-gpu inceases the numbers, and it just so happens that they fit well within the processing limits offered by a single R500/R600/R700 gen gpu...each offers more shader processing elements than the competition, adn this allows for gains using dual-gpu mode for single cards.


SKTMTL, there's other engiens that offer this, and I'm sure you'll see the same sort of gains there as well.

[DarKStar]

Interesting - I wonder if this would have any effect on my GeForce 8800GT OC 512MB... I'll have to test this one day if I have some time

[magictorch]

This looks promising for ATI- for a single card anywayin some game engines. But this means running dual GPUs in a game like COD4 has even less of an effect. Wonder if Age of Conan or GRID works in the same way as they also scaled well with cf.

Anyway cant seem to find enable dual GPU in my control centre for 8.6 though- Id like to see this boost for myself and try it out in a few games.

[SKYMTL]

The issue is that there are not that many games with an SLI / Crossfire toggle in the game itself.

[magictorch]

Ok thanks SKY, missed that.

Anyway quick game-play contrast in COD4 starting at the same point for 60secs:

FRAPS 1680*1050, XP, everything possible maxed out
Dual/Single GPU enabled:Min 95/59, Max 171/143, Avg 136.089/80.656

Only running at stock 2.66 on the new board right now as I'm going through stability tests before I start to OC again tomorrow.

Ill edit this later when I have more data.

[ne5a]

Yeah this is just a glitch in cod4 which is a horrible game to begin with. For some reason selecting the single video card actually caps your performance while selecting dual uncaps it. Stupid setting, I know.