Can't get RAM to work at 200Mhz while overclocking

[Loki86]

Hi,

I've got a problem overclocking my System (see signature )

I wanted to overclock my San Diego to ~2970Mhz.

These are my settings :

FSB Bus Frequency : 270

LDT/FSB Frequency Ratio : x3.0

CPU VID Control : 1,550V

CPU Special Control : Above VID * 104%

LDT Voltage Control : 1.30V

Chip Set Voltage Control : 1.60V

DRAM Voltage Control : 2.70V

---

DRAM Frequency Set : 166=RAM/FSB:05/06

Command Per Clock : Enable

Cas Latency Control (TCL) : 2.5

RAS# to CAS# delay (Trcd) : 03 Bus Clocks

Min RAS# active time (Tras) : 08 Bus Clocks

Row precharge time (Trp) : 03 Bus Clocks

Row cycle time (Trc) : 07 Bus Clocks

Row refresh cyc time (Trfc) : 14 Bus Clocks

Row to Row delay (Trrd) : 03 Bus Clocks

Write Recovery time (Twr) : 03 Bus Clocks

Write to Read delay (Twtr) : 02 Bus Clocks

Read to Write Delay (Trwt) : 03 Bus Clocks

Refresh Period : 3120 Cycles

 

Now every time I try to use these settings, the pc hangs at the second screen after turning power on (shortly before windows starts) and restarts after some seconds. When I set the DRAM Frequency to 133 Windows boots, but then the RAM just works at ~175Mhz. The other settings like 140 or 150 also don't work.

 

I already tried updating the BIOS to the latest version, but that didn't work either.

Does anyone know how I can get this to work ?

 

P.S.: With normal settings everything works fine, I've got this PC for quite some time now and never had problems, but now I wanna do a bit of overclocking.

[CPDMF]

Max Async, Read Preamble, and Tref will have an effect on CPU OC. Try loosening up Max Async to 8.0 or even 9.0 and read preamble to 5.5 or 6.

[Loki86]

I've tried doing this settings, but it doesn't work either :sad: :mad:

 

Anyone got another idea what to do ?

 

Thanks !

[TheRock]

Yep, I've tried it too.

I have same cpu as you, btw.

It runs at 2.2GHz, i could OC it to 2.3GHz when i left ram at 200mhz then in order to OC more I had to downclock it to 180mhz, and I'm runing at 2.5GHz atm.

I don't quite get it because my ram was supposed to be designed for OC, yet I had to dc it.

[q0nk]

FSB Bus Frequency : 270

---

DRAM Frequency Set : 166=RAM/FSB:05/06

 

Looks like you memory cant handle the speed:

 

270x5/6=225

 

PC3200 memory = 200

 

You either need PC4000 = 250

Or change the divider to around 200.

I have a different board, so I'm not sure twhich divider settings you have

[Loki86]

according to this calculator http://home.arcor.de/xxmartin/Calculator/

the RAM speed ist 212 Mhz at my settings and according to my tests (MemTest 86 from the BIOS) I found out that the RAM should work with 225, but it's the limit, at 230 MemTest got errors.

But the problem is, that even if I choose a lower divider, for example 150 or 140 it doesn't work, altough the RAM should work with these dividers at less than 200Mhz.

Even at a FSB Bus Frequency of 240 it doesn't work (I think at 235 at worked).

[q0nk]

can someone explain why the speed of the ram changes in that calulator when the multiplier changes? i just dont get it

[Loki86]

I really don't understand it..as I mentioned before, when I set the RAM Divider to 133 it works, but when I set it to 100 it doesn't..

Very strange, why doesn't it work if I set the divider lower ? I think it's not the RAM thats making trouble but the mainboard/bios itself, I can't find any other explanation than this.

But how can I solve this ?

[cuoficr]

Its a problem with odd dividers, set your CPU/RAM to 1:1 and load memtest at 200mhz fsb and write the bandwith down, do the same for 210/215/220/225 then set your CPU to whatever FSB and set your divider, use memtest to check the bandwith, it will give u the real speed the ram is running at, and its the memory controller/ram combination, some just DO NOT get along

[TheRock]

But at 215 and 1:1 mem to fsb ratio, the comp won't even boot up, in my case.

[Loki86]

Ok, I made some tests with Memtest, here are my results :

 

FSB200 : 1702 MB/s - CPU@2200Mhz

FSB210 : 1842 MB/s - CPU@2311Mhz

FSB215 : 1886 MB/s - CPU@2365Mhz

FSB220 : 1930 MB/s - CPU@2420Mhz

FSB225 : 1974 MB/s - CPU@2476Mhz

-------------------------------------------------

set the RAM Divider to 166:

FSB235 : 1772 MB/s - CPU@2585Mhz (RAM @ 184Mhz)

FSB236 : 1779 MB/s - CPU@2596Mhz (RAM @ 185Mhz)

FSB237 : 1786 MB/s - CPU@2607Mhz (RAM @ 186Mhz)

FSB238 : 1794 MB/s - CPU@2618Mhz (RAM @ 187Mhz)

FSB239 : doesn't work

-------------------------------------------------

set the RAM Divider to 133:

FSB270 : 1707 MB/s - CPU@2971Mhz (RAM @ 174Mhz)

 

Does this mean the RAM at the last settings is as fast as it ran on 200Mhz (with normal settings) altough it only runs with 174Mhz?

 

EDIT : All these results have to be a little bit higher , I forgot to set the command rate back to 1T, now at FSB270 I've got 1842MB/s

[cuoficr]

set the RAM Divider to 133:

FSB270 : 1707 MB/s - CPU@2971Mhz (RAM @ 174Mhz)

 

Does this mean the RAM at the last settings is as fast as it ran on 200Mhz (with normal settings) altough it only runs with 174Mhz?

 

EDIT : All these results have to be a little bit higher , I forgot to set the command rate back to 1T, now at FSB270 I've got 1842MB/s

it means the mhz speed of the ram isnt being accuratley reported. the actuall speed of your ram should be roughly 210Mhz, where are you getting the 174 Mhz from?

 

:edit:

 

CPU multiplier * Divider = Memory divider, Then CPU speed / Memory Divider = Memory speed.

 

using the 11 multi makes the 180 divider 11/12 not 9/10 as the BIOS States