Need help!

[Guest]

Hi guys,

i've got a mess in my head about memory timings and that is what i like to discuss here.

I've got a Q6600 quad core CPU. The FSB is 1066Mhz so 266Mhz quad pumped. This means I need to use 533Mhz RAM at least. What I have at the moment is 800Mhz at 6-6-6-18. How can I get the best performance out from this If I tighten my timings to 4-4-4-12 and reduce the speed to 533Mhz or leave it at 800Mhz at 6-6-6-18?

Any help would be greatly appreciated!

Krisztian

 

[jsc]

Definition time (attention purists, I'm simplifying a little ):
Core2 CPU's use a frontside bus (FSB). The FSB is a thing with two main characteristics: speed which is usually defined in MHz and width which in the Core2's is 64 bits wide. We are concerned with the speed.

Using the Q6600 as an example, the FSB frequency is 266 MHz. The matching DDR2 memory clock for that frequency is 533 MHz (266 X 2). DDR2 memory transfers two chunks of data for each bus cycle.

The FSB clock is 1066 MHz (266 X 4). The bus is "quad pumped". It transfers 4 chunks of data into and out of the CPU each cycle.

Now, if you increase the FSB frequency to 333 MHz, the corresponding memory clock is 667 MHz and the FSB clock is 1333 MHz.

I always run my memory at 1:1. That is the FSB freq to memclock ratio is one to one. That means that the memclock is twice the FSB freq. It's a little confusing.

Running memory slower costs performance. Running memory faster does not give you much if any real world performance increase and it can lead to higher instability.

Here's a thread where we talk about it:
http://www.tomshardware.com/forum/251715-29-ratio-myth

You can probably run your Q6600 at 3.0 GHz with the stock cooler and little or no core voltage increase. In this case, change your memory clock divider (or whatever it is called) from AUTO to 2.00. Increase your FSB freq to 333 MHz. and your memory clock frequency should be like 666 or 667 MHz. This will give you a CPU-Z ratio of 1:1. At this point, you will gain more performance by tightening your timing than trying to OC your RAM.
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Overclocking since 1978 - Z80 (TRS-80) from 1.77 MHz to 2.01 MHz

 

[knotknut]

JSC is right on.

Sence you are running DDR2 800 try this set-up
http://www.tomshardware.com/reviews/dual-quad,1720-15.html

Without knowing the quality of your Ram you might want to start at 5-5-5-15 at the default voltage printed on the Ram or from the Ram manuf. website.

 

[Guest]

Thanks guys for the help! I really helped a lot!

Thank you!

Krisztian