Jump to content
Corsair Community

PC3500 A7N8X2.0 2500+ XP-M Prime95 unstable @ 2.4GHz


Recommended Posts

I am looking for some help in acheiving stability on my first Barton OC setup.


Previously I could run 2xCMX256A-3200C2 (TwinX PC3200 512) modules, dual channel (slots #1 and 2) stable at up to approx 2 GHz (166 fsb x 12.0, 1.575 Vcore). In all cases below the DDR speed equals the FSB by BIOS default.


I didn't have to make changes to any DDR voltages (auto) and the timings were 2.5-3-3-6 if I recall correctly.


I saw a deal on PC3500 (2x CMX256A-3500C2, BH5?) which I grabbed and tried to do the following with the DIMMs in slots #1 and #3:


200 x 12.0 , 1.675 Vcore, DDR voltage (auto, 2.6), Timings 2-2-2-5


I POSTed, got into WinXPSP2 and ran Prime95 torture test at the default choice. My first test failed due to a rounding error so I backed off a bit.


200 x 11.0, 1.675 Vcore. DDR voltage (auto, 2.6), Timings 2-2-2-5


Same as before and my first Prime95 test failed again due to a rounding error. This would make my PC3500 setup less stable than with my PC3200.


Confused, I went for a known stable baseline with my last pair (PC3200):


166 x 11.0, 1.575, DDR voltage auto, Timings 2.5-3-3-6.


These settings POST and test fine for Prime95.


Surely this new PC3500 RAM of mine can help me hit 2.4GHz on air cooling or at least get me as stable as my old setup?


What am I doing wrong? And right?

Link to comment
Share on other sites

hey mate...with a mobile you need to do the wire trick to make it think its a 200mhz chip...if not it has trouble over 190mhz...


i will find you some pics and instructions...use a piece of old ide wire about 6 mm long..just one thin piece of copper from there...


gimme a while

Link to comment
Share on other sites

Here's what seems to work


200x11.5, 1.60Vcore, DDR V auto, FSB Spread 0.50%,: Prime95 Stable at 2-3-3-6 with the CMX256A-3500C2 or 2.5-3-3-8 with CMX256A-3200C2.


I performed a PCMark04 Pro set of 16 memory tests and get around 2706 for PC3200 and 2766 for PC3500. I don't know if this is a good bench for mem.


That being said, having PC3500 in my system made it noticeably quicker during booting. I think this RAM is wasted in my current setup so off with it.


I was not aware of any wire trick but I'll have to check it when my OEM wty expires 8)

Link to comment
Share on other sites

the wire trick is actually a mod to the socket..and its been around for over a year now..maybe more.


its one of the only ways to make mobile athlons prime stable over 190 mhz.... you have to force them to believe they are a 200 mhz chip


hope this helps



mad andy

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...