Hello,
First off, many people will tell you to not buy Generic Memory even if your planning on overclocking while others will tell you it's ok. Currently, I have 384 megs of Generic memory in my computer with a Duron 600 OC to 900 without any problems. However, I do not change my FSB in overclocking my processor. If you have a Tunderbird Class of CPU you can use the Pencil trick to unlock the multiplier and do not need to change the FSB. If you have an Intel CPU then the only way you can overclock is by the FSB. Changing the FSB of the processor does change the speed at which your RAM runs, but there are ways you can combat this.
If your processor runs at 133 mhz, depending on your shipset you may be able to SUBTRACT the PCI clock from the FSB. In essance, non-overclocked your RAM would run at 100 mhz. Overclocking the CPU would make the PCI bus and the FSB increase in MHz, however, with this setting you would not hit 133 mhz, you'd probably hit somewhere inbetween 100 to 110 or so, depending on how much you can overclock the CPU. Then again, the RAM might be able to take the increased bus speed and work perfectly fine at 140 mhz or however high you decide to overclock the processor...
I hope this helps... Name brand IS the way to go, but some of us don't have the money to spend, especially with these generic prices