Help with research for new pc

[mogwai]

I have started looking into a new Core 2 Duo based pc and am a bit confused as to why when all the Core 2 Duo's listed on the site have a FSB of 1066 Mhz, that all the bundles only come with 800 Mhz Ram.

Surely you would want the RAM at the same speed as the FSB otherwise you are introducing a bottleneck?

 

[mogwai]

bump

 

[Big.Wayne]

At stock a Core2 Duo needs PC2-4200 (DDR533) . . . the external clock of the mobo is 266MHz which is then quad pumped to reach approx 1066MHz-FSB . . . The memory doesn't need to match the quad-pumped FSB speed, it needs to match the external clock speed . . .

 

[mogwai]

So how does the PC2-6400 RAM which is 800 Mhz and PC2-8500 RAM which is 1066 Mhz fit into the picture.

If I where to get one of the E6700 with a motherboard that suppots 1066 FSB and not overclock would the above types of ram just be slowed down to 233 Mhz?

 

[mogwai]

So if you run the PC 6400 RAM at stock in conjunction with E6700 core 2 duo, what frontside bus do I end up.

As with my current rig a P4 c 3 Ghz with PC3200 ram I have an 800 Mhz FSB which I thing is 200 mhz x 4. So how does this translate to core 2 duo.

 

[Big.Wayne]

Its very similar to how your P4 works . . .

P4 3.0GHz (15x200)

External Clock:200MHz (quad pumped to 800MHz-FSB)
Multiplier: 15
Resulting Frequency: 3000MHz
Memory neededC3200 (DDR400) i.e runs at 200MHz

So you need memory that can run as fast as your external clock.

The thing that has changed now is the newer CPU's run using a higher external clock (266MHz) which is still quad pumped (1066MHz-FSB)

PC2-4200 - DDR533 (i.e runs at 266MHz)
PC2-6400 - DDR800 (i.e runs at 400MHz)
PC2-8000 - DDR1000 (i.e runs at 500Mhz)


e6300 1862Mhz (7x266)

External Clock:266MHz (quad pumped to 1066MHz-FSB)
Multiplier: 7
Resulting Frequency: 1862Mhz
Memory neededC2-4200 (DDR533) i.e runs at 266MHz

Hopefully you should be getting the idea now