Understanding DRAM Final clockrate

[HutchtheGhost]

I've been reading the guide on overclocking and I have a few questions to make sure I'm understanding everything correctly.

I'm using a Q9450 which runs at 8x333 = 2.6 ghz by default and 2 sets of Corsair TWIN3X2048-1333C9DHX which is rated at 1333.

My question is regarding DRAM final clock rate and how it is calculated for DDR3 as that is what I'm using.

From what I gather there is no difference in the equation at all between DDR2 and DDR3.

Therefore since I'm running at 333 FSB stock and my memory is rated up to 1333 I could potentially run up to 666 FSB in linked and synced mode.

Due to the fact I'm running async mode right now with manual configuration of 1333 the ratio 1:2 was automatically picked as 333 * 2 = 666 (DRAM Frequency) and 666 * 2 = 1333 (DRAM Final clock rate).

Are these assumptions correct?

 

[MaDMagik]

You got it right, its just that 1333 is the number of data transfers, not "final" clock-rate, as it doesnt finally run at 1333Mhz but 667Mhz(dram freq).

 

[HutchtheGhost]

Perfect, what sort of performance increase do we see from running ram in faster than 1:1 with FSB? Is there any advantage or disadvantage?

What I gather is that it just creates troubleshooting nightmares so people stick with link/sync when doing a simple OC.

 

[randomizer]

This article should answer your question: http://www.madshrimps.be/?action=getarticle&number=1&artpage=1962&articID=472

It's old but it gives you an idea of what to expect since the memory and FSB architecture of Core 2 hasn't changed since 2006.

 

[HutchtheGhost]

Excellent, thanks for the prompt replies everyone. Going to memtest my RAM this weekend and attempt a 3.0ghz ish OC.

On a side note, does anyone with a EVGA 790i Ultra know where the PCIE setting is to lock it to 100 so I don't burn out the slot when it tries to scale with FSB? I posted in motherboard area but noone seems to know.

Wish me luck,

Hutch

 

[randomizer]

Perhaps it's locked by default. Most motherboards do automatically lock it. Having it unlocked won't burn out the slot, but it will cause severe instability and probably failed boots.

 

[jsc]

Just leave the PCI settings alone. If you do not touch them, they will automatically stay at 100 MHz.