Page 23 - A little CPU Scaling

CPU scaling with the G80 

CPU Scaling. The i680 SLI test system is now equipped with a selection of processors and we'll look at performance differences with cheaper CPU's on a CPU limited game (Far Cry) and a game more rough on the GPU (Prey). This was requested in our forums prior to the release of this article and at the last minute I decided to do something with it. Now I simply did not have the time to build an AMD platform to test yet the processors used are all Core 2 Duo in a variety of flavors. The X6800, E6700, E6600 end budget E6400. The E6600 is a perfect example of a FX-60 performing processor where the E6400 can be compared with the performance of a AMD Athlon X2 5000+

Obviously this is merely indicative, but I wanted to show you the performance differential with processors. What we try to prove here is how immensely important it is to have a high-end CPU with configurations like these.

So again we take Prey and Far Cry, Far Cry especially as it is a very CPU bound game. Let's have a look. First we'll look at Prey with a chart for the GTS and GTX.

Before we begin, I mislabeled the E6400 falsely in the charts, it's says E6300 it obviously should be E6400.

So above we have the GTS at work. We scale from the high-end 2.93 GHz clocked Core 2 Duo X6800 Extreme processor to your right the 2.13 GHz E6400 processor over a wide variety of resolutions. As you will observe throughout this page we do have CPU limitation, yet not as bad as I expected though. Where lines go flat you have some sort of bottleneck. But when lines go flat at the same level over multiple resolutions that would be CPU limitation. A state where your graphics card can render the games faster yet your CPU can't deliver data fast enough to the graphics card driver.

Mind you that we are testing with the best in-game IQ settings and with 4xAA and 16xAF.

Here we have Prey again, but now with the GTX. We can see that beautifully in the lower resolutions that we are CPU bound as the effect of a faster processor is very visible. For the GTX results I also added the results of an overclocked stated. In this case we pushed a Core 2 Duo processor towards ~3.5 GHz which obviously increases performance. The difference between the XGURU processor ;)  And E6400 at 10x7 is 38 FPS.

So what kind of effect would that have on a CPU bound gaming title like Far Cry you ask? Have a look below.

Here we see Far Cry with the BFG GeForce 8800 GTS. You can see that the budget E6400 processor definitely takes a toll, but for that kind of money that's not bad at all.

The last result I wanted to show you today was on the GeForce 8800 GTX. Again we have the XGURU processor and look at 10x7, wow that's a 55 FPS differential. So to the question is the GeForce 8800 series CPU bound ? Yes, it most certainly is.

Well you'd think we should be near the end of this article right ? Nope coming up GeForce 8800 GTX SLI results!