N00B overclocking help

[asdfqwertyuiop]

I've got my E6600 and my P5B-E Plus mboard with 4 * 1GB Corsair PC2-6400 RAM (CM2X1024-6400C4).

Just trying to work out my settings for OC.

Corsair says:

Tested at EPP SPD settings (4-4-4-12) at 2.1V
SPD programmed at:
JEDEC standard 5-5-5-18 values at 800MHz
EPP standard 4-4-4-12-2T, 2.1V values at800MHz


Why are there two sets of timings, 5-5-5-18 and 4-4-4-12-2T?

The ram will also do 5-5-5-15 with 2.2V and DDR2-1066 (according to Corsair) - http://www.xbitlabs.com/articles/memory/print/ddr2-800.html

So my RAM is definitely good up to 2.2V and 533MHZ.

At the moment I've got my FSB at 320MHz, my ram's at 4-4-4-12@2.1v, and it's stable after 20 hours of Orthos.

I've set the RAM divider to 5:4, so the RAM's running at its rated DDR2-800 speed. Is this a good idea? What is the purpose of RAM dividers. It seems like it makes the RAM faster than FSB, so essentially you need higher quality RAM, but I guess it might make the PC faster as the RAM is running at a higher frequency. Do RAM dividers aid in boosting overall CPU clockspeed at all? Or is it just to get a bit higher performance by driving the RAM faster?

In boosting my OC, what should I fiddle with? I don't want to push things too hard, no point in stressing things in getting an extra 100MHz of CPU.

I guess put RAM timings to 5-5-5-15, RAM volts to 2.2, and then tighten the timings when I get a stable OC. Should I use RAM dividers?

Obviously FSB is the main thing, but how about the other voltages?

I can fiddle with:

CPU Vcore - what's a conservative setting for this?
FSB termination voltage ???
Northbirdge VCore
Southbridge Vcore
ICH Chipset Voltage

 

[GuitarDaddy]

There are two sets of timings because all P965 chipset boards only give 1.8v by default so ram makers set the SPD timings looser so the boards will boot the first time with 1.8v, once you up the volts to the 2.1v spec you can tighten the timings up to 4-4-4.

And yes the memory multis are so you can run higher speed ram without overclocking the FSB, which does give a small performance boost.

For testing your max CPU overclock you should use the 2.0 mem multi or 1:1 divider as you call it, that way you can overclock the FSB up to 400 without pushing your ram over spec. For an easy jump from your current 2.88 to 3.2 you could drop the cpu multi to 8 and increase the FSB to 401, this will probably only require a small increase in vcore while leaving the other chipset voltages on auto. And with the 1:1 divider your memory will be at stock DDR2-800, so you would use 2.1v 4-4-4. It's quite possible you can get these settings to work with the 9x cpu multi resulting in 3.6ghz but it will almost certainly take a more substantial bump in vcore.

If your not comfortable with the vcore and temps required for 3.6ghz you can go for 3.3-3.5ghz by using the 8x multi and upping the FSB into the 410-440 range which may require upping the NB, and FSB term voltages and will require you loosen memory timings and up the ddrv. I recommend this because the board loosens the internal timings (FSB strap) once you go over 400fsb, making it easier to overclock the FSB in the 401-450 range than in the 350-390 range.

 

[asdfqwertyuiop]

Originally posted by: GuitarDaddy
There are two sets of timings because all P965 chipset boards only give 1.8v by default so ram makers set the SPD timings looser so the boards will boot the first time with 1.8v, once you up the volts to the 2.1v spec you can tighten the timings up to 4-4-4.

And yes the memory multis are so you can run higher speed ram without overclocking the FSB, which does give a small performance boost.

For testing your max CPU overclock you should use the 2.0 mem multi or 1:1 divider as you call it, that way you can overclock the FSB up to 400 without pushing your ram over spec. For an easy jump from your current 2.88 to 3.2 you could drop the cpu multi to 8 and increase the FSB to 401, this will probably only require a small increase in vcore while leaving the other chipset voltages on auto. And with the 1:1 divider your memory will be at stock DDR2-800, so you would use 2.1v 4-4-4. It's quite possible you can get these settings to work with the 9x cpu multi resulting in 3.6ghz but it will almost certainly take a more substantial bump in vcore.

If your not comfortable with the vcore and temps required for 3.6ghz you can go for 3.3-3.5ghz by using the 8x multi and upping the FSB into the 410-440 range which may require upping the NB, and FSB term voltages and will require you loosen memory timings and up the ddrv. I recommend this because the board loosens the internal timings (FSB strap) once you go over 400fsb, making it easier to overclock the FSB in the 401-450 range than in the 350-390 range.

So what's going to be fastest - faster RAM speed, or tighter timings?

E.g., if I leave things at stock (FSB 266 MHz), then my options are:

1:1 divider - DDR2-533 4-4-4-12
3:2 divider - DDR2-800 4-4-4-12
2:1 divider - DDR2-1066 5-5-5-15

Which would fastest?

 

[GuitarDaddy]

Options 2&3 will both be faster than 1, between 2&3 it's a tossup. Option 2 may actually be faster than 3