memory divider not working! a8n sli-deluxe

[gazzy]

Hi. I have a asus a8n sli-deluxe mobo and i try to set a divider to my memory so it runs at DDR 400. In the bios the memory divider is called max memclock, this is set to 400.

Im running an amd 64 3200 winchester. stock 2.0 ghz. oc'd to 2.25
crucial ballistix 4000 2 * 512MB

When i boot in to windows and run cpu-z the memory is reporting a speed 225 and so im assuming that the divider isnt working. Although the ram is more than capable of running at this speed that isnt the point.

Anyone got any ideas?

thanks in advance

[theuncharmed]

If you set the RAM to run 1t 400 it will run at those speeds at stock. If you overclock then it raises.

eg. I have a 144 and I have my RAM is set to run at 333. It actually runs at 410 because the CPU is at 250 and the divider ration between the preset 400 at stock and 333 = 5:6 and therefore 250/6 x 5 / 2 = 205

!?!

sorry in other words its fine. if you want it under 200 - set it to a 333 setting.

[gazzy]

Not sure im with you.

So is it the ratio that matters and not the value I set?

Dont why asus have to use this sytem rather than a ratio system.

My RAM is at 1T, been trying to work out if lower latency is better for 3ds max work or raw speed hence this quest with my divider. My ballistix arent stable at high frequency and low timings plus 1T.

[gazzy]

Also how did you arrive at that calculation you showed in your post, what settings are you reffering to?

[theuncharmed]

333/400 = 5/6

FSB = 6
RAM = 5

at stock settings for example of 2.0 Ghz with the RAM at 400 and the CPU clock at 200.

When you raise the CPU Clock as you have done so increases the speed of the RAM but at the same ratio. So a 300 CPU clock is running RAM at 250.

Asus do use a ratio its just not shown as a ratio usually is.

Becase of the AMD built-in memory controller you dont actually take much, if any, of a performance hit if you use a divider so its a good idea to drop it maybe further (if needed) and run 2-2-2-5 1T timings.

[arthurleung]

A64 CPU treat divider slightly different from Athlon XP / Intel
For example you run your CPU at 300x9 (2.7Ghz), 266 Divider, it runs at DDR385(CPU/14) or DDR415 (CPU/13) but not DDR399 you would expect.

The ratio is CPU:RAM not HTT:RAM, always take that into account when overclocking memory. Motherboard manufacturers made the 266/333/400 thing so that normal (i.e. don't know how to overclock) will just think if they using DDR333 then run 333 setting. The board itself will get the ram speed close to DDR333 so that the ram would work not too much out of spec

[gazzy]

cheers guys.

I'll have a dabble and see what I come up with. See if I can get the best out of my cpu. Looks like its should be stable at a nice high frequency and im using an akasa evo 913 so i got decent cooling.

Also. Do you know if overclocking via the HTT puts more strain on a chip rather than if you had a chip with an unlocked multiplier?

[iranu]

At the moment you have your Ram speed:FSB ratio set at 1:1 (which is the default setting)

therefore fsb = 225, Ram =225.

You can change the speed at which ram operates on an AMD 64 system by using a "divider". The divider changes the Ram speed:FSB ratio.

It is usually given as a percentage of FSB or as a ratio (e.g 5/6 or 0.83333 or 83%)

with a FSB of 225 the Ram will operate at the following speed with the following divider

1:1 (100% or 1) - 225x1=225Mhz
5/6 (83% or 0.833) - 225x0.83=186.75Mhz
3/4 (75% or 0.75) - 225x0.75= 168.75Mhz

settings under 100% or 1 are used when you are overclocking the cpu (increasing fsb) but the ram is unable to operate at a 1 to 1 speed. Using a divider under 100% keeps the speed of the ram down yet allows the cpu to run at a higher fsb.

You have the opposite where your ram is capable of a higher speed than the cpu's fsb.

Some motherboards have the option of running the divider at a ratio greater than 1:1 or 100% but i would not recommend using those dividers for an unexperienced overclocker. Keep it at 1:1 for the time being.

Also. Do you know if overclocking via the HTT puts more strain on a chip rather than if you had a chip with an unlocked multiplier?

Overclocking using the fsb is generally faster as the rest of the system will run at this speed. "Strain" on the chip - I presume you mean heat - will not matter eitherway. The only upwardly unlocked amd 64 chip I know of is the FX5* series. Your 3200 winchester will be multi-locked unless you have been very lucky. I would keep the HTT multiplyer at 3 and continue to increase your fsb in small amounts whilst monitoring temps adn running some benches to see if things are stable for the time being.