Memory speed question

[trents]

I recently purchased DDR2 1066 to replace DDR2 800 because I was anticipating moving up to an AM2+ capable CPU, which I have done. My question is, is there any advantage at setting the "Memory Clock" in bios to x5.33 (1066 mhz) instead of x4.00 (800 mhz) without changing other parameters such as the speed of the fsb? The cpu is running at 3.0 ghz (15x200) in both cases. The only difference I can see in CUP-z is the divider is now 3/8 instead of 1/2. Does this mean that setting the memory clock back to x4.00 is actually better? Or, will the higher memory clock give me better performance in some types of computing?

I should add that I using this ram with an AMD triple core cpu and the 2x2gb ram is configured in single channel mode because the system is unstable in dual channel mode. That's another story.

[18 is # 1]

Run Everest both ways and measure.

[trents]

Okay, I ran Everest in three different bios configurations with regard to memory. CPU (Toliman 8750 be) is clocked to 3.0 ghz for all three test modes. Memory speed and fsb are the test variables. HT speed kept around the default 1800 mhz.

With fsb at 200 mhz and ram speed at 800 (200 with a 4.0 multiplier):
Mem read=5982 mb/s
Mem right=4664 mb/s
Mem copy=5510 mb/s

With fsb at 200 mhz and ram speed at 1066 (200 with a 5.33 multiplier)
Mem read=7223 mb/s (+20.7%)
Mem write=4665 mb/s (no gain)
Mem copy=6170 mb/s (+12%)

With fsb at 250 mhz and ram speed at 1000 (250 with a 4.0 multiplier):
Mem read=7424 mb/s (+24%)
Mem write=5674 mb/s (+21.6%)
Mem copy=6197 mb/s (+12.4%)

Conclusion: Increasing ram speed to from AM2 (800 mhz) to AM2+ (1066 mhz) levels while keeping other bus parameters at the same speed gives small to modest gains in memory operations. Increasing the memory speed and the fsb yields significant gains in memory operations. Of course, it always needs to be said that this is a synthetic test and real world computing tasks may not show as much difference.

[wingman99]

Real world has not shown me any difference.:(

[18 is # 1]

The processor speed will always make the most difference. Higher FSB is the way to go.

[Bandit1]

Thanks.Informative.Makes sense to get the most speed out of ram providing it can't do much tighter timings @800.I have also noticed how playing with trc makes a real world difference with my am2 setup..I am pretty new to this,really.