The Tips in detail

 "RAM pays alot more than CPU-power."

This is true, if you are having less than 256MB and try to wrestle with more than aprox. 150K faces, since 3DSM25+ swaps everything. Swapping means a dramatic decrease of performance, since accessing HDD is by far slower than accessing RAM.

Look at what your system uses from what is called "virtual memory" while rendering and modelling using the Taskmanager (provided you are using NT). If you are hanging on Win95/Win98, you might be able to estimate this value by observing the size of the pagefile (the Windows swapfile.)

Try to get that much RAM that Max doesn't need to access the "virtual memory" (The later one is actually a portion of your swap-file on your HDD. If you already installed loads of RAM you might notice that Max still swaps to your HDD... thanks to the OS...) Having enough RAM means most of the time an average increment of speed around 10-30%, depending on the configuration of the individual machine and software (see also: "MAX swaps everything to your HDD.")

If you have to keep an eye on your buget you should consider upgrading RAM above upgrading the CPU since the later one is more expensive for the same increment of power.

Purchasing RAM: Keep in mind how many RAMslots your MotherBoard has and and how they are epuiped now. Make up your mind about how much RAM (in MB) you are going to buy and how to get the most outof what you already have. Compare this to the amount of RAM you want to have in the next time: stay flexible and calculate the loss of value. Bigger modules are more expensive but you can instal a larger total of MBs into your system. Also keep in mind that RAM is a gimmick with dramtic changes in price. Although prices tend to fall over the time the market has proven to be jumpy with sudden increases up to doubling the price within days and slowly lowering later. Check the vendors when you are out to purchase RAM and ask somebody you know to buy hardware on a regular basis to get a good price.