Abit NF7-S FSB

Hi, I am new to the overclocking scene so my question will be simple.

When I boot up, running my Barton 2600+ (166x11,5) I get a message that my ram is running at 400Mhz. Can this be possible, considering my FSB is only at 166? This is when I have the ratio from my DRAM set at "By Spd". If I turn it to "Auto", it will show the speed of the RAM to be 2xFSB, 333mhz, which seems more logical.

Will having the "By Spd" option run my RAM at 400Mhz (ddr400 ram), or does it just say so in the startup? Do I have to change my cpu to run at 200x11,5 if I really wanted to get everything out of my DDR400 ram?

Oh yeah, also, when I changed the speed of the CPU to 180x11,5 and having "By Spd" selected for the DRAM ratio, the boot up screen would say my ram speed to be something like 430Mhz (don't remember the exact number). Does this mean I am also overclocking my RAM?

Can RAM run faster than the FSB? That is pretty much what my question comes down to. Can 180x11,5 really have RAM running at over 400Mhz?

Fairly simple answer to this question.

Since the ram is DDR (Double Data Rate), a 133 mhz FSB on the cpu equates to 266 mhz FSB on the ram.

If your ram is running @ 430 mhz, and your ram is rated for 400 mhz, then you are running your ram overclocked.

I don't know what kind of motherboard you have, but it is best (on AMD platforms, anyway) to run the RAM in sync with processor FSB.

jus set it to 6/6

When I boot up, running my Barton 2600+ (166x11,5) I get a message that my ram is running at 400Mhz. Can this be possible, considering my FSB is only at 166?

Click to expand...

They havent fully explained what ur seeing soooo:

You CPU and RAM are running what is called "asynch". Asynch is used to run the CPU and RAM at different default speeds. Asynch is very popular for Intel guys. Their bus speeds far exceed their possible RAM speed so thus they run it outta synch.

Running in such a configuration is accomplished using "dividers". Thus you are using 2:3 right now. This means that for ever 3 units of RAM effort, the CPU puts out 2 of its own.

What these pplz want you to do is run "synch"ed with the RAM. Synch is a 1:1 basis between the RAM and FSB.

Thus setting 1:1 / 3:3 / 6:6 would cause the RAM to sychronize with the bus. This would then allow you to run:

200 (DDR400) : 200 (DDR400) mhz as apposed to you current setting of:

166 : 200

Can RAM run faster than the FSB? That is pretty much what my question comes down to. Can 180x11,5 really have RAM running at over 400Mhz?

Click to expand...

Yes, once again your divider setting is currently 2:3. So thus....

2 : 3

166 : 400

+20 : + 20 (aprox) cant remember the equation

180 : 430

Setting you dividors to "6/6" would allow you to OC to default 3200+ speeds by OCing the bus to 200mhz. This is what they were trying to tell you in a round-a-bout fasion.

I hope this helped

-Sen

also...
WELCOME TO THE FORUMS
...and the sickness

Thanks for the great answer People aren't always that helpful with such newbie questions, so thanks!

My aim is to get my 2600+ running at 200x11,5
But I am worried this might be a little too much with just air cooling? I'm using a rather silent fan on a copper heatsink. I'll also have to up Vcore a tad too if I do it, and that is still quite a secret science to me.

So now, if my processor is running at 180x11,5... is it better if I run RAM asynch at 400mhz, or will I actually receive BETTER performance if I run the RAM synched, at only 360mhz? This is 400 vs 360, but there probably isn't that 40Mhz advantage in actual practice?