cyborg939

I am planning to overclock a Q6600 G0 with a 780i. Which memory should I get, DDR2 1066 or DDR2 800? If I set the FSB at 400 and the multi @ 9x, what should the mem divider be if I use DDR2 1066? Is there any way to calculate the memory divider? Is it automatically determined by the BIOS? Thanks for helping a noob overclocker.

dralb

I have never used that board, so I am not sure how the divider is labeled. Your choice of RAM depends how ,uch you want to overclock it. Most (if not all) 1066 RAM is just 800 RAM overclocked from the manufacturer, so most people here go with good quality 800 and overclock it themselves to save money. I am a fan of the Crucail Ballistix. They use great IC's and the 800's can clock to 1066 with 5-5-5-12 timings. I have seen some people get to 1200 with higher voltages.

As far as what divider, this depends on the FSB you end up running. If you go with 400 FSB, yo can run your RAM 1:1 at 400mhz at stock settings. You could also run a 4:5 divider and run it at 500mhz. It all depends on what RAM you get. Once you get the CPU OC dialed in, figure out what divider will give you what RAM speed. Set it and run a bootable memtest for 2-3 passes to see if it is stable.




edit: Also, there will probably be an auto setting for the divider. If you overclock, you should manually set the divider so as not to overclock the RAM too much.




OK, to try to be clearer, my RAM runs at 800mhz, 4-4-4-12. The same model sold as 1066 runs at 533mhz, 5-5-5-15. I can manually set mine to 5-5-5-15 and have it running at 544mhz (435 FSB with a x2.5 (4:5 ratio, listed as a 2.50 multiplier in my BIOS) RAM divider. I could run 1:1, but why not get the most from your RAM?

__________________
Antec 1000 Case Mod Worklog

3358 Windsor 3800


"[Vietnam] only made billionaires out of millionaires. Today's war is making trillionaires out of billionaires. Now I call that progress." -Kurt Vonnegut

CD in response to whether folding is a waste:

Cyant

On the 680i/780i boards you can set the memory speed in manual mode by selecting / typing the Mhz you want. The board will then select the appropriate ratio to get that exact speed or the closest speed rounded down of what you selected.

Choggs396

This is true. You do not have to calculate the ratios yourself - the board will do it for you. Just set the Front Side Bus and Memory speeds independently.

Just for reference, a 1066MHz FSB is a "Quad-Pumped" or Quad Data Rate of 266MHz x 4. The "actual" 266MHz Front Side Bus is doubled to determine DDR speed. The "stock" memory speed would then be 533MHz. (For a 1:1 FSB:RAM ratio). The final CPU frequency of the Q6600 is 266MHz x 9 = 2,400MHz.

The 400 x 9 you are referring to is a 400MHz FSB (or 1600MHz QDR) multiplied times 9 to determine the final CPU frequency of 3,600MHz. In that case, the Memory speed would indeed be 800MHz (at a 1:1 ratio), or 400MHz x 2 (DDR).

__________________
Fore Sale: X850XT Platinum Edition PCI-E - $30 shipped

I did error10's Windows Challenge and Windows now runs me!

Je pense, donc je suis
- René Descartes

Overclock.net Professionalism Initiative

Higach

I have a question to add to this. Is running 400Mhz on a 2:3 divider easier on the ram than running 400Mhz on a 1:1 divider?

only reason I ask is because I have 2 sticks of ram, 1 works fine both 266x8 2:3 400Mhz and 400x8 1:1 400Mhz, the other can do 266x8 2:3 400Mhz, but can't do 400x8 1:1 400Mhz.

Same model too..

Cyant

Must be something else, probably the motherboard. Because 1:1 or 2:3 or whatever other ratio don't affect the ram itself if the speed result is the same. If it's running at 400Mhz with the result of the ratio then it's running at 400Mhz no mather what the ratio is.

The ratio is only a reference on which the motherboard use to determine what it will set the memory clock generator frequency based on the FSB frequency.

Higach

that doesn't explain why 1 stick works fine but the other stick doesn't work. The good stick proves that the mobo/cpu etc is capable of 400x8 3.2ghz, and it starts up fine. When I switch the sticks I get all the problems, and windows wont even boot. I turn it on, it beeps twice before anything is on the monitor, and it restarts and resets the overclock.

Anyway, I have a feeling the stick of ram is crappy. I got told by a G-skill technician that 1:1 is harder than 2:3.. which I don't understand at all, and I could only RMA if it didnt work on stock settings. I ordered a new stick since its only like 25 bucks, but I still wish I coulda fixed the cruddy stick.

Higach

Ok now it gets interesting... I bought the third stick.. It came about 20 minutes ago... and it works perfectly just like the 1st stick.

1st stick runs fine 375-400x8 1:1, 3rd stick runs fine 375-400x8 1:1, 2nd stick can't get past 313x8 1:1, and when I try i just get 2 beeps and a restart/reset.

So what does this mean? Is it a bad stick? or just a bad OCer (But how is running at 400Mhz on a 1:1 ratio OCing when its ddr2-800??)

I posted again on the g.skill forums, and asked the technician what I can do, but chances are all I'll get is "if it works at stock speeds (266x8 2:3 and it does) then theres nothing I can do"..even though clearly theres something wrong with the 2nd stick.

Any thoughts?