Need some quick and urgent advice on bottlenecking :O

[wentalong]

Hey all,

My mates asked if i wanted to buy his R1 M15x from him and i've said im interested however there are some problems:

First off the laptop only has the intergrated card as the old GPU he had in there broke some how which means im going to replace it with a 6990m or something mad like that,

But the laptop has a crappy celereon its using atm but im going to upgrade that to a core 2 extreme x9000 aswell,

so what i need to know is if the 6990m will be bottlenecked by the x9000 and if so which GPU Wont be bottle necked by the CPU?

Many Thanks Everyone!

 

[Duff-Man]

"Bottlenecking" is generally a misunderstood term - here is perhaps a better way of looking at things.

Suppose you're playing a game. A somewhat simplified (but essentially accurate) way of looking at the issue is this:


Within each frame of the game, a certain amount of work has to be done by the CPU (the game logic, AI, and most other stuff), and a certain amount of work has to be done by the GPU (mainly rendering). If the CPU finishes its workload first, you must wait for the GPU to finish before the frame can be sent to the screen. In this case you are "GPU limited", for that frame. If instead the GPU finishes its work first, then you're CPU limited for that frame.


Two quick points about this:

First point: The balance between CPU and GPU limitation will change not only from game-to-game, but also from game scene to game scene. One scene may be particularly CPU heavy (e.g. swarms of AI units on screen) and thus CPU limited, while another may be GPU-limited (e.g. loads of particle effects) and this GPU limited. The term "CPU bottlenecked" implies that the CPU is always (or nearly always) the limiting factor. Unless you have an abysmally slow CPU, then this is very unlikely to be the case. The balance between CPU and GPU will depend on what game you are playing, and what's going on on-screen right now.

Second point: There is nothing necessarily wrong with being CPU limited! Certainly it doesn't make things "grind to a halt"; instead it just means that your GPU has spare capacity (at this moment). Putting a slower GPU in will never improve your framerate by removing a "bottleneck". Being CPU limited also largely removes the microstutter associated with dual-GPU solutions, but that's another discussion entirely.

So, to answer your question: It's impossible to say "xyz cards would be bottlenecked by abc CPUs", without knowing the precise application. Just go for the fastest CPU and GPU that you can afford. And yes, that CPU will perform very well alongside the 6990m.

 

[wentalong]

ahh thanks for the explanation mate, it was brilliant! and i was just worried about splashing all that cash on the 6990 when it'll never be used to its full potential and so i thought it may be more economical to buy something not as good, like the 6950m etc,

Thanks!

 

[Duff-Man]

Well, it may still turn out to be more economical to buy a slightly slower GPU, but it's probably got more to do with the resolution you're gaming at and the games you're planning to play, rather than your CPU speed. The best thing to do is check some benchmarks for the games you're planning to play.

 

[wentalong]

thanks mate, my friend brought the upgraded m15x with the 1920x1200 however im not to fussy playing a game at 800x600 lol, will most likely grab a GOU first then see how it goes then a x9000, many thanks!