GAX48-DS5 Overclocking

[JasonRitchie]

Hi All,

I have been trying various overclock tests and quite often I get a lock-up wilst running Prime95 on 'lots of everything' test after about 10 minutes with the CPU clock >375. If I run the 'lots of cpu a little ram' test then the machine is stable. If I run with a CPU clock <375 I can do the 'lots of everything' test indefinitely.

Using Speed Fan I can see the CPU temp at 50-60 and core0 at about 68 in the worst cases. Is this too high?

Do you think the lock-up is due to the NorthBridge overheating because lot's of ram is being tested which puts the NB through it's paces and it can't take it? I'm thinking the problem is heat as it takes about 10 minutes on full load to expose the problem.

It looks quite difficult to cool the NB as it is half under the first HD4870 graphics card and the next HD4870 is not far away! I'm thinking of trying to squeeze a small fan on top of it and see if that helps.

I can go through this more methodically if someone from gigabyte is listening.

On another note, is it worth me installing the beta bios? I used to be running it for ages but I had a checksum error on the bios yesterday and it reverted back to F5.

Any help is greatly appreciated. I'm sure it's possible to get this system to run with an FSB of 1600Mhz / 1700Mhz stable.

[JasonRitchie]

I've just realised my stupid mistake!

I was getting my North Bridge mixed up with my South Bridge.

The North Bridge is next to the CPU not under the PCI cards. Doh!

I can see now that the heatsink on the NB is much more substantial. Is it any good just resting a fan on top of the heatsink or should I try to remove the top plate which seems to block any airflow between the fins?

Again, any help is greatly appreciated.

[JasonRitchie]

Update:

I have had some good success!

I have managed to hang a small 50mm fan on top of the NB heatsink. I have ended up using some throw away cable twists to tie it in position against cables and brackets.

The results are good. I am now able to get a stable system running Prime95 on 'lot's of everything test' without lock ups or failures and the case is all fully closed up with one case fan at the back.

I have updated the bios back to F8a again. Don't know whether that has helped or not.

Anywaym here are my settings:

Robust Graphics Booster___________ [Auto]
CPU Clock Ratio ____________ [8]
Fine Clock Ratio ____________[+0.0]
CPU Host Clock Control_ [Enabled]
CPU Host Frequency (MHz)__________ [425]
PCI Express Frequency (Mhz)_______ [AUTO]
C.I.A. 2__________________________ [Disabled]
Performance Enhance_____________ [Standard]
System Memory Multiplier (SPD)____ [2.66D]

DRAM Timing Selectable________ [Manual]
CAS Latency Time________________5
Dram RAS# to CAS# Delay_________5
Dram RAS# Precharge Delay_______5
Precharge Delay (tRAS)__________ 15

ACT to ACT Delay (tRRD)_________5
Rank Write to READ Delay________ 6
Write to Precharge Delay_________ 6
Refresh to ACT Delay______________ 50
Read to Precharge Delay__________6
Static tRead Value_______________12
Static tRead Phase Adjust________Auto
Command Rate (CMD)____________Auto

CPU/PCIEX Clock Driving Control [800mV]
CPU Clock Skew Control [normal]
GMCH Clock Skew Control [normal]

System Voltage Control____ [Manual]
DDR2 OverVoltage Control__ [+.30v]

PCI-E OverVoltage Control_ [+0.10v]
FSB OverVoltage Control___ [+0.10v]
(G)MCH OverVoltage Control [+0.20v]
CPU Voltage Control_______ [1.38v]


So, this points to the fact that on these boards the NB heatsink needs the additional cooling to get reliable overclocking to work.

I will do some more tests to see if I can improve the FSB further or the RAM timings.

If anyone has the ideal setting for the Crucial Ballistix I have then let me know.


Thanks,

J