Upgraded to 8GB - Lower OC

[PCJake]

I have been running 4GB (G.Skill DDR2 800, 2x2GB) for many months at 925MHz without problems with an FSB of 370, 5-5-5-15 timings with Refresh to ACT Delay set to 55, and a 2.50 divider.

Today I got another set (identical to the first) of 4GB of RAM. I reset my BIOS to optimal defaults (GA-EP35-DS3L board), put in the RAM and redid the overclock. I got a BSOD, so I pulled the cmos battery for a minute or two and tried it again. Now the system is stable with a 2.40 divider (888MHz), but not with a 2.50 divider (925)MHz.

Is this likely do to some individual variation in the RAM chips, so that the new ones aren't able to overclock as well? Is there anything else I can try?

Thanks!

 

[chizow]

Could be the new RAM chips don't overclock as well, as you were running those DDR2-800 sticks considerably faster than the rated speed. Could also be a memory controller/chipset/bios/mobo limitation as its not uncommon for boards to be less stable with 4 dimms populated.

Easiest way to check if you know which dimms are new and old is to run the 2 new sticks by themselves at your old memory clocks and timings and see if you're stable. If that's the case and the 2 new sticks are stable at the old settings, your board may not be as stable with 4 dimms populated, so you may have to lower clock and/or loosen timings.

 

[n7]

Up MCH voltage, or perhaps vDIMM as well.

Make sure tRFC (Row Refresh Cycle Time in Asus, i dunno what GB names it) is loose (55+).

First thing i would do though is test the RAM individually...maybe the new kit cannot do DDR2-925...

 

[PCJake]

I have the MCH overvoltage set to +.1, but I could easily go to +.2, assuming it's safe. The settings under MCH overvoltage are listed in light colors (not dark or red), so I would assume that they are relatively safe to change.

After I pulled the cmos and redid the overclock (2.50 divider), I no longer got a BSOD, but the P95 tests failed almost immediately. I don't mind that as much as a BSOD, so maybe I'll try changing the voltage first.

 

[Idontcare]

I have some DS3L systems and I must admit I am impressed you got any stable OC whatsover with all four dimm slots populated with 2GB sticks.

When you double the sticks of ram in your system it doubles the capacitance which makes your signal/noise ratio go to pot. Same reasons going from dual-core to quad-core puts a serious dent into the max stable FSB OC.

Just trying to help possible adjust your expectations down a little bit. My DS3L's run 367MHz FSB and my sticks of 2GB DDR2-800 ram are intentionally underclocked (1:1 multi) so I avoid any stability issues such as the ones you are experiencing.

 

[PCJake]

Originally posted by: Idontcare
I have some DS3L systems and I must admit I am impressed you got any stable OC whatsover with all four dimm slots populated with 2GB sticks.

When you double the sticks of ram in your system it doubles the capacitance which makes your signal/noise ratio go to pot. Same reasons going from dual-core to quad-core puts a serious dent into the max stable FSB OC.

Just trying to help possible adjust your expectations down a little bit. My DS3L's run 367MHz FSB and my sticks of 2GB DDR2-800 ram are intentionally underclocked (1:1 multi) so I avoid any stability issues such as the ones you are experiencing.

I hadn't though about it in that way, thanks.

I'm still quite happy with 370fsb and 2.40 divider, and I'll probably let the computer run for a couple days (on top of some more P95 tests) before I try anything else.

It's pretty cool to be able to play Call of Duty 5 perfectly while having Cinema 4d use over 5GB of RAM. I also use this machine to edit RAW photo files, so I think the small sacrifice of speed is worth it.