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Geforce SLI

Stalker: Clear Sky - Micro stuttering with Geforce GTX 260 SLI

In the current issue of our German print magazine, we published a detailed article about micro stuttering. Now we have another obvious example with Stalker: Clear Sky.
Stalker: Clear Sky (Bild: PCGH)
 
Stalker: Clear Sky (Bild: PCGH) [Source: view picture gallery]
Micro stuttering is not restricted to a single producer. Nvidia, Ati/AMD and S3 Graphics use the same multi GPU rendering: Alternate Frame Rendering (AFR). In the print article we visualize the frame displacement of a Geforce 9800 GX2, a Radeon HS 4870 X2 and a SLI combo with two GTX 260. The latter one had by trend the hardest micro stuttering problems. And it's the same with Stalker: Clear Sky.

In our DX10 Benchmark Review we also checked multi GPU solutions. While the Radeon HD 4870 X2 delivered an excellent performance with an unobtrusive amount of micro stuttering, the GTX 260 SLI had problems with an irregular frame output again. We made a video that can found below the text. The system we used was equipped with a QX6850 on an Nforce 680i SLI motherboard with 2x 2,048 MiByte DDR2 RAM. The operating system was Windows Vista x64 SP1 and the driver was the Geforce 177.92 Beta.

Please pay attention to the fact, that the framerate usually stays between 30 and 40 fps and only drops below 20 when we zoom in.


--
Author: Raffael Vötter (Sep 10, 2008)


Downloads
Stalker Clear Sky - Mikroruckler [122,7 MB]





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Comments (2)

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pcghx_Kristoffer Re: Stalker: Clear Sky - Micro stuttering with Geforce GTX 260 SLI
Administrator
10.09.2008 15:55
Quote: (Originally Posted by Yapa)
I dont actually know what micro stuttering is? Can you explain more about it?

Is it the very small 'stutter' as you move around screen? And is it only visible on SLI/multi gpu solutions?

I have never noticed it... why does Stalker CS have it and other games do not etc?

Anyway to see the print article on the web?

Yapa


Hello Yapa, and welcome to the forum.

Micro stuttering is a problem of graphics cards or graphics solutions with more than one GPU. The basic idea is that the GPUs calculate the individual frames in turns and thus each GPU would have to calculate a lower number of frames. You can think of it like this: GPU 1 delivers the first frame and 5 milliseconds later GPU 2 delivers the second frame. After an additional 5 milliseconds GPU 1 delivers the third frame and so on. Unfortunately it happens that the output of the GPUs is not synchronized and the pattern changes as follows: GPU 1 delivers frame 1. 8 milliseconds later GPU 2 delivers the second frame and 2 milliseconds after that, GPU 1 delivers the third frame. The framerate would still be the same as in the first example but some people experience the irregular frame output as stuttering. Since this is not the same as normal stuttering, which is caused because the graphics card is not powerful enough, the two versions of stuttering are differentiated by calling the multi GPU problem micro stuttering.

I hope this rough explanation was helpful. (The times I used for my examples don’t match the real time graphics cards usually need to calculate a frame. I just used any numbers to explain the problem.)

Stalker Clear Sky is not the only game that suffers from micro stuttering, since the problem is caused by the multi GPU solutions and not everybody recognizes it. We already experienced micro stuttering in several games. The most popular ones are Crysis, Unreal Tournament 3 and Call of Duty: Modern Warfare.
Yapa Re: Stalker: Clear Sky - Micro stuttering with Gef...
Senior Member
10.09.2008 14:26
I dont actually know what micro stuttering is? Can you explain more about it?

Is it the very small 'stutter' as you move around screen? And is it only visible on SLI/multi gpu solutions?

I have never noticed it... why does Stalker CS have it and other games do not etc?

Anyway to see the print article on the web?

Yapa

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