LogieBear said:
They are equal, its like the triangle of a gaming P.C
All three are required really
A better analogy I think is a tube (series of tubes!) no just a tube where you have to have a lot of data flowing freely for it all to be moving fast enough to get high framerates.
If any one section of the tube is too narrow that would be a "bottleneck" in the system and the added advantage of this is that in computing that is exactly what it is called:
Q: "Aww, why is my Source engine game stuttering when I'm running an 8800 GTS at only 1280x1024"
A: "your system has a bottleneck with your 3GHz Pentium 4"
To the OP:
All the data needs to be handed around your system with ease. And it isn't just speed but bandwidth too, you need adequate memory caches all along the chain or the system will be forced to do things by halves or quarters or may not be able to do them at all.
So the questions is not "what can I scrimp on" but "What do I HAVE to get right on a first build/buy"
And I'd say that is the CPU- and by extension, the motherboard. See upgrading the RAM and GPU is a piece of cake, but you can't put DDR3 RAM into a motherboard that doesn't accept it nor use a CPU in a socket that lacks adequate pins.
I think it is telling that the consoles of this generation have really quite weak GPUs for their launch date yet very powerful Central Processors, Triple core for Xbox 360, 1 +6 (+1) cores for the PS3 (1 main core, 6 daughter cores for gaming, 1 daughter core for the OS, 1 spare daughter core disabled for high yields). Kinda indicates the importance of powerful central parallel-isation of processing this generation.
The best value at the moment seems to be with Athlon II X2 processors.
But I worry if they have the same growth potential as going for an LGA-775 socket.
Bottom line, get a system which has a CPU that can handle all the games you want to play today and next year. But make sure it is of a socket type that you can easily upgrade the CPU in 3-4 years to get a good 5-6 years of useful life out of the system.
Remember, in 5 years time, 8-core processors may be the norm for gaming, I know, sounds crazy for calling something like that, but 5 years is 3 cycles of Moore's Law, three times the price and size of hardware will roughly half.