Sign in with
Sign up | Sign in
Your question

CPU vs Ram FSB question

Tags:
Last response: in CPUs
Share
April 27, 2008 11:10:59 PM

I'm building a computer with the following components.

XFX nForce 790i Ultra SLI Socket 775 Motherboard

Intel Core 2 Quad Q6700 2.66Ghz CPU

Crucial Ballistix 2048MB PC12800 DDR3 1600MHz

Here is my question,

The mb has a 1600 fsb, the cpu is 1066 and the ram is 1600.

Now, is it that the ram is really 800fsb because of the funky way they calculate it, or, is it that the ram runs faster than the cpu fsb meaning it will be stepped down to the cpu speed?

More about : cpu ram fsb question

April 28, 2008 12:52:04 AM

Ram will be running WAY faster that the CPU, as it goes off clock fsb which on the CPU will actually be 266mhz ("Quad pumped") and the RAM clock will be 800mhz.

Currently you dont really need DDR3 as it has little to no performance gain and is very expensive.

To run a Q6700 then minimum you can have is DDR2 533mhz
April 28, 2008 2:03:18 AM

thanks for the quick response,

ok, so here is another question, does that mean that the ram will run slower to match the cpu, or do they run their own speeds independently?
Related resources
April 28, 2008 3:46:18 AM

Im not positive with DDR3 but i think the lowest spec it will run at is 800 because thats the lowest DDR3 spec. But you can increase it so that you are at a better ratio then 1:1 CPU:D RAM
April 29, 2008 6:41:00 AM

They run independently, but since all data going to/from the RAM has to go through the FSB, if the FSB is running at 1333MHz, there's not much point running the RAM faster than DDR2(or 3)-667MHz.
April 30, 2008 3:46:48 AM

Mondoman said:
They run independently, but since all data going to/from the RAM has to go through the FSB, if the FSB is running at 1333MHz, there's not much point running the RAM faster than DDR2(or 3)-667MHz.


But DDR3 wont run that slow will it? thats out of the scope of standard specification
April 30, 2008 8:28:33 AM

You can run the RAM at a faster speed, but the data will slow down to 1333Mhz datarate once it hits the FSB.
May 1, 2008 4:07:16 AM

Yeh i realise that...

so you are saying that DDR3 wont run slower than 800mhz?
May 1, 2008 7:48:31 AM

chookman said:
Yeh i realise that...

so you are saying that DDR3 wont run slower than 800mhz?

800mhz datarate. That is the slow speed set by JEDEC for DDR3.
That is really a 400mhz bus with double data rate.
DDR3 has higher latencies, so DDR2 running (overclocked, since JEDEC does not recognize anything over 800mhz datarate for DDR2)@ 1066 will outperform DDR3 at the same datarate.
At anything less than 800mhz datarate, DDR3 is a major loss.
!