Hi,

A real noob would appreciate some advice here. The basics of my rig are the following :

Asus Maximus Formula mobo
Intel E8400
8800 GTS (320mb)
2 X 2 gig sticks of OCZ 6400 (800Mhz) Ram

I recently overclocked the CPU by upping the CPU Frequency to 400 so I'm running at 3.6ghz. I had my memory timings on auto and I see in CPU-Z (and my bios) that my timings are 6-6-6-18 (2T). After much research this did appear high to me especially as my RAM's timing is listed on OCZ's site 5-4-4-15. Does anyone else agree that 6-6-6-18 is too loose ? Is this due to me overclocking my CPU ?

I changed my BIOS settings to Manual, then tired to tighthen the timings a tad to 5-5-5-15 (1T). This failed in PRME95 after a couple of mins. I loosened the TRAS gradually all the way back to 18 but was still not stable. I tried each upping each one individually but the only way I could get it to run stable is changing all the timings back to 6-6-6-18 (but now at 1T). Should I try again at tightening the timings but at 2T which is what set to on Auto .. will 1T or 2T maken any difference ?

Also , I kind of understand the CPU:RAM Ratio. To some extent anyway. What I'm confused abuot is what is the actual speed my memory is running at. For the all the above , my CPU:RAM Ratio has always been 1:1. Does this mean that my RAM is only ever running at 400mhz ? Do I need to change that Ratio to 1:2 to get my RAM to run at 800Mhz. I mean, I think I understand that my RAM definitely needs to run at at least 800mhz for my CPU overclock to be stable. CPU-Z depicts my RAM frequency at 400mhz and my CPU:RAM Ratio as 1:1. What is my speed ? Or because it's dual channel do you automatically times the 400mhz by two to get your speed.

Also, can anyone comment on the fact that when I change from 2T to 1T in my BIOS , that CPU-Z still shows 2T ??

I'm quite confused and miffed that I can't get tighter timings on this RAM which is supposed to quailty RAM. Any advice would be most appreciated. Sorry, would post screenshots of CPU-Z but I'm at work and this has been on my mind all day !!

Cheers

Just a further note as I'm reading (and clearly not working). The following is from an OC'ing article on the E8400 :

"Due to the E8400 using a 9x clock multiplier, it is simply a matter of adjusting the CPU FSB to 400MHz in order to reach 3600MHz. For stability reasons we recommend you manually set the 'PCI Express bus' frequency to 100MHz when overclocking. Depending on the memory you are using, we also suggest setting the memory multiplier to 2x, which on a 400MHz FSB will result in a memory speed of 800MHz. Given that most use DDR2-800 memory, this will ensure that the system remains stable"

Is the 'memory multiplier' they're talking about above, the same as the CPU:Ram Ratio ? As mentioned, mine is set at 1:1 and this is what makes me think I'm only running my RAM at 400mhz ?? Help !

Wow, that's a bunch of questions

I may not cover all your questions. But I will share my knowledge:

1) CPU:RAM ratio?

I will put an example on my system: (with all stock speed)
proc E6750 that's FSB1333 with 2.66GHz
ram Corsair DDR2-800 (PC2-6400)

my mobo has a native FSB 1333. The actual bus speed is actually = FSB/4 = 1333/4 = 333

now my RAM is DDR2-800. DDR is double data rate, so it means that it's actual RAM speed is half of it = 800/2 = 400MHz. Now where do they get PC2-6400 name? Well it's simply 800*8 = 6400 I guess this answering your question on your actual RAM speed. (ps: your cpuz will read this actual speed 400MHz).

OK, so now come the ratio:
remember that my RAM is DDR-800 (400MHz actual) and my FSB is 1333 (333MHz actual bus speed). Now to get my system working, the RAM should match the FSB, and here's the ratio. On my system that can be achieved by setting DRAM : bus ratio = 6 : 5. (FSB : bus = 400:333 = 6:5).

2) multiplier?

What about multiplier? The multiplier is needed to get processor speed (in my case at stock = 2.66GHz). To achieve this, I can set multiplier to 8. Basically:

Proc speed = bus speed x multiplier
So:
2.66 GHz = 333 x 8

3) ....

Sure you can do the other way:
I can set my DRAM : bus to 1:1 and run my bus at 333 MHz and downgrade my RAM speed to 333MHz (equally DDR2-667).

Or you can do vice versa (overclocking) set my bus at 400 MHz (OC) which match my RAM speed 400Mhz at 1:1 ratio. Thus we can get 3.2GHz (400x8).

... hope it helps ... somebody do correct me if I'm wrong ... (I'm so sleepy now that I can mistyped or anything ... )

Antus you are completely correct. I had some similar questions as firc_ops_gordo and found the same advice as you have given. All of it seemed to offer me some real peace of mind regarding my RAM speed.