That leaves me with underclocking the CPU to match the RAM freq. I believe this should make my system more stable ( atleast compared to overclocking ) and have a little more life than before?
There really isn't any reason to do that. The CPU issues a memory request and waits for the "data valid" signal to come back from the memory controller. There's no harm nor anything to go wrong in this whatsoever. It's designed to work like this.
Is your system actually unstable at the moment? If not, why change anything? If it is unstable, I'd suggest looking elsewhere for the problem, maybe PSU or a dodgyfied windows installation or driver. You shouldnt have to resort to running under-spec to get things working properly.
Don't worry about the longest possible life from our hardware. Intel gives you a 3 year warranty on a retail CPU and that's more tha enough time to get your investment out of it. In 3 years, all the apps will require greater horsepower and it forces people to upgrade. That's like saying I'm not gonna turn on the lights in my house because I want the lightbulbs to last as long as possible or I'll drive with my lights off at night and just use moonlight because I want my headlights to last as long as possible, lol.
To the guy that still has the 8086. I have no doubt it boots perfectly fine but the fine booting doesn't run Crysis or make Windows 7 snappy does it?
This is cool - I came to know about 3 new things just from this thread:
1. [ainarssems] I would set FSB to 400Mhz x4, RAM ratio to 1:2, this would have Your CPU running at 1600MHz bus and RAM @800Mhz.
2. [ainarssems] If You want You can drop CPU multiplier lower to 7 (2.8GHz) or 6 (2.4GHz).
3. [mrmez] drop voltages
I have no clue into the details of any of these, so I need to ask questions:
1. What would be the benefit of running the CPU faster than the RAM? Specifically running the CPU at twice the freq of the RAM? Would it not make the CPU wait twice the time for RAM to respond?
The reason why I want to "underclock" is to make sure the CPU does to burn idle cycles just waiting for the RAM to respond - or does it not work that way?
2. By dropping the CPU multiplier, would not the RAM and CPU be "out of sync"?
3. Are benefits of undervolting a CPU documented somewhere? I am not sure about microprocessors, but in case of microcontrollers, undervolting leads to serious electrical glitches!
These things are new to me so help me out here :-)
One thing is for sure - this sure is interesting!
Only got time for 3: Read my comment in the brackets above. Undervolting WITHOUT compromising the proper operation of the device. That means that some times you can't underclock at all. Sometimes a better quality process or whatever can help you underclock your CPU a little bit. Hence why use more power, excess heat etc when you can do exactly the same job with less? Help the environment we say!
> What would be the benefit of running the CPU faster than the RAM?
The CPU will run faster when it's not waiting for stuff from the RAM. Most memory accesses are found in the CPU's cache and therefore the CPU only goes and reads stuff from RAM for perhaps 10% of the memory accesses. And the CPU does lots of other things beside memory accesses, too. So it makes absolutely no sense to slow down the CPU just because it occasionally needs to wait for RAM. It would be like lowering a freeway's speed limit to 50 km/h just because that's the speed that cars enter and leave it at.
> By dropping the CPU multiplier, would not the RAM and CPU be "out of sync"?
The CPU is hardly ever "in sync" with other components in the system anyway. The protocols between the CPU, the FSB and the other components ensure synchronization only when it's needed (ie, if I read something from RAM and it's not ready yet, I wait 'till it's ready). To use another analogy, there's no point limiting the speed of a transit bus to 5MPH just because it carries people who walk to the bus. The bus stops to pick up or drop off passengers, just like the CPU does when it can't proceed without data from another device.
> I am not sure about microprocessors, but in case of microcontrollers, undervolting leads to serious electrical glitches!
You can undervolt microcontrollers too, but not very much. The same thing applies to CPUs. We're only talking about small fractions of a volt.