OCZ SLI PC6400 Ram Underclocking to 533?

[grindy]

I had a PC which I've recently upgraded. It originally had 2 GB of PC 6400 OCZ Nvidia SLI Ram. CL 4-4-4-12 timings @1.8V (based on the label)

When I moved to Windows 7 64bit I bought another 4 GB of PC6400 OCZ Nvidia SLI Ram. This ram has CL 5-4-4-15 timings @2.1V (based on the label)

When I run a CPU-Z or look in my BIOS my Ram is setting itself to 533MHZ and something stupid like 6-6-6-18 timings. My recent attempts to adjust it have ended up with the system failing to post and then automatically booting back up with the stock AUTO settings of 533MHz, 6-6-6-18 timings.

I will post images of all the details in CPU-z and the BIOs Images, but can anyone think of a good reason for this happening? Nothing else on the system is overclocked at the moment and my "attempted" timings were 5-4-4-15 @ 800Mhz and 4-4-4-12 @ 800Mhz.

CPU: E4300 @ 1.8Ghz
Mobo: Gigabyte GA-EP45-UD3L
Ram: 2Gb OCZ Sli 4-4-4-12/4Gb OCZ Sli 5-4-4-15
HDD: WD Velociraptor 150Gb
Video: Radeon HD4870
P/S: OCZ PowerStream 500W

 

[xoke]

Sounds like your motherboard is confused from having 2 different sets of RAM in there.

Let me see if I have this right though...in CPUz it is saying your running them at 533mhz right? ...

If yes, remember that CPUz shows actual RAM mhz, not the DDr effective mhz...meaning your RAM (right now) is actually running 1066mhz effective (533mhz actual). Your RAM is rated for 800Mhz effective (400mhz actual), so, while you are running way beyond it's rated speed, you are also trying to tighten up the timings...causing FAIL.

So, my theory based on what I know now is that you need to manually set the RAM to 800mhz effective (400mhz actual) via BIOS, manually set the timings based on the weakest set (CL 5-4-4-15), and manually set the voltage based on the highest set (2.1v). If all goes well you will boot into windows and CPUz will show you are indeed running all of it at 400mhz actual, which is 800mhz effective DDr2.

All RAM has a mhz speed (ie...400mhz), DDr RAM reads on the up and down clock cycle (thus it's name DDr, double-data-rate). So while the actual speed of said RAM is indeed 400mhz, it pumps out info at an effective 800mhz.

DDr 800 = 400mhz
DDr 1066 =533mhz
DDr 1333 =667mhz
DDr 1600 =800mhz

CPUz reads the second set of numbers...dig?

 

[coonmanx]

Post the memory page of CPU-Z along with the SPD pages showing both of the different ram chips (whatever those slots may be).

 

[grindy]

As requested here are the CPU-Z shots

 

[trents]

Try putting just the slower modules (the new ones) in the board, set the bios to DDR 400, look in CPU-Z to see what timings it gives the newer ram (if it will boot, that is). Then put all the sticks back in and set the timings to what the slower ram wants to run at.

Also, is there a differential in what the two kinds of ram are rated for as to stock operating voltage? If one set requires a higher or lower voltage than the other, it could be too much or too little for the other set.