Bottlenecking?

[safehaven]

I am mainly asking for educational purposes. Is there a way to tell ahead of time where your system is going to bottleneck, prior to adding new parts? Is there like an online calculator or something of the sorts? Or, do you just have to have common knowledge about how the parts work with one another?

For example. I have a E6320 OCed @ 3.2 GHz, 4 GB or PC2 8000, 500W EW PSU, WinXP32. Will a 5870 GPU be bottlenecked by my CPU? How do you know for sure, or do you ever know for sure?

This is just an example. I am planning on buying a new video card in the near future, but it definitely will not be a 5870. It will probably be a 5850, 4890, or 5770, depending on how much I want to ante up.

 

[keenan]

It depends heavily on the application. This is why reviews benchmark several different games/apps and the results are often wildly different; each application loads the system differently and may end up being limited by any component - this is fairly common to see in benchmarks of new components.

As a general rule, if you change the resolution of a game and the framerate doesn't see a corresponding increase/decrease, you're CPU limited.

 

[Dangman]

I am mainly asking for educational purposes. Is there a way to tell ahead of time where your system is going to bottleneck, prior to adding new parts? Is there like an online calculator or something of the sorts? Or, do you just have to have common knowledge about how the parts work with one another?

It's just common knowledge and experience. The general rule that Keenan noted is mostly true. I do have a quote about it:
[A good way to find out if your GPU or CPU limited]

First drop the resolution to as low as it will go, and turn all settings on low. You may even be able to tweak the game to stop rendering some objects, and really drop the graphics quality. If your frame rates don't improve whatsoever, then your CPU/platfrom is limiting your performance. So you would then know, that upgrading your GPU will not bring that game to playable levels.

However, if you find that by lowering your settings to such a disgusting degree, actually brings the game to a playable level. Then an upgrade of the GPU will let you turn the settings up, and your CPU should remain up to the task.

And then there are just some CPUs that you can tell automatically or from others experience that it will be a bottleneck. For example, pretty much any AMD Athlon X2 CPU at or below the X2 6400+'s speed will be a bottleneck in games. As for your current CPU, that's a bit more complicated due to sheer performance already offered by the C2D CPUs. Its a bit hard to believe that a C2D based CPU that's been OC'd will be a major bottleneck

 

[sirmonkey1985]

it really depends on the game more then anything.. also if you plan to run the game at 60 fps or at a high resolution and/or how much eye candy you plan to run.. the cpu should be fine with a 5850 or 5770.. but plan on upgrading the cpu later on down the road as newer games continue to come out..

 

[engiNURD]

Since GPU's are the fastest depreciating component in a gaming pc, I think the best thing to do is wait until you current card no longer plays your games at the desired resolution/settings. When upgrading that card, read reviews and look at its performance in the games you play, and be sure to note how each review tests their cards (eg. [H]ard|OCP test methodology is very different from AnandTech).