Timings on RAM

[715]

No.  Auto normally sets looser timings and lower voltages to be "safe".

It must depend on the motherboard: both of mine use the SPD values.  In fact that was a problem with the older Intel board: the SPD was too fast for the board but it set it to that anyway.  I had to manually slow it down.

[715]

I've got a question.  I understand that FSB:DRAM of 1:1 is desirable.  How do you accomplish that? 

For example, I just built a system based on a 8400 and Gigabyte GA-EP35-DS3L MB.  Its stock now; the CPU is at 3GHz and the "bus" is 333.3 MHz with a 9X multiplier.  The memory is 400 MHz (DDR2 PC2-6400) with FSB:DRAM of 5:6.  How do I get 1:1?  Do I just up the CPU "bus" clock (presuming it can keep up) by 6/5 to reach 3.6GHz?  Will that give just a 12% increase in benchmark or better because of better meshing of CPU and RAM?

[BaldEagl]

I've got a question.  I understand that FSB:DRAM of 1:1 is desirable.  How do you accomplish that? 

For example, I just built a system based on a 8400 and Gigabyte GA-EP35-DS3L MB.  Its stock now; the CPU is at 3GHz and the "bus" is 333.3 MHz with a 9X multiplier.  The memory is 400 MHz (DDR2 PC2-6400) with FSB:DRAM of 5:6.  How do I get 1:1?  Do I just up the CPU "bus" clock (presuming it can keep up) by 6/5 to reach 3.6GHz?  Will that give just a 12% increase in benchmark or better because of better meshing of CPU and RAM?

You have two options; overclock the CPU or underclock the RAM.

Most motherboards have an option in the BIOS under advanced chipset features to ""Link" the CPU and RAM clocks and another to "Sync" those clocks.  To underclock the RAM to 1:1 just link and sync and save the changes.  This will lower the RAM clock to 333.3 and you're linked and synced at 1:1.

To overclock the CPU you first have to disable Intel Speedstep, Thermal Control and C1E Enhanced Halt State.  You also want to disable all Spread Spectrum settings and Link and Sync the RAM.  All of this is done in the BIOS.

Next, set the CPU core clock to 400 or the FSB to 1600, whichever the BIOS allows you to adjust.  Set the CPU voltage to auto, then back it down 2-3 notches (It will auto set too high).  Boot up and if you boot normally run Orthos or Prime95 through at least 5-10 strings using small FFT's.  If that runs normally, restart entering BIOS.  Turn the voltage down two notches and try again.  Keep doing this until you no longer boot or until you get Orthos/Prime95 errors, then go back to BIOS and up the voltage one notch and re-test.

The key is to get it stable with as little voltage as possible.  Over volting causes heat, so monitor your temps continually while doing this.  If you run over ~60C shut down and lower your CPU VCore.

At 400 clock speed at a 9 multiplyer you will be at 3.6 Ghz.  If you can't run cool and stable (which you should be able to do without problems) at those settings, lower the multi to 8 and you'll be running at 3.2 Ghz which will allow you to run at lower voltage, thus with less heat.

[Getback]

Well, you would do it just as you proposed.  You'de raise the core clock from 400 to whatever number you wanted (within reason) but would also have to loosen timimgs (from say 4-4-4-12 to 5-5-5-16) and raise voltage for very little if any gain.

Furthermore, if you recall, I urged you to OC you CPU to 3.6 Ghz to sync your clock speeds at 400, which you did.  Now you are proposing to un-sync the RAM, which means that the RAM will be waiting on your CPU for data.

Synced clocks eliminate any bottlenecks from the process.  Un-synced clocks will run as fast as the slowest component, so, unless your willing to OC your CPU higher to match your new higher RAM clock you will gain nothing and likely have stability issues as well.

Good luck.

I'm leaving it alone. Thanks for the input  

Btw, I'm sending the E8400 back and the E8500 has a 9.5 multiplier. So that would take it to 3.8. That's plenty.