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First overclock - CPU voltage & RAM question

  • Overclocking
  • RAM
  • CPUs
Last response: in Overclocking
July 16, 2010 10:11:46 PM

I have decided to overclock my 'old' (2.5 year old) computer.

I have the following
Q6600 G0 stepping (running at stock since purchased)
GA-X38-DQ6 motherboard
4xCorsair dominator 1066 RAM
Xigmatek HTD-x1283 cooler (bolt on kit) - just purchased this week
Radeon HD-5870
Silverstone OP1000W PSU

The first run of Prime95 with round checking on at stock speeds failed after 11 mins (I've never done round checking so it prob would have done this on the old cooler as well)

I used to have problems running 4x1Gb at 1066 on this board (even with MCH+0.1 and DDR+0.3 at 5-5-5-15) so I have been running the ram at 800 4-4-4-12 with MCH+0.1 and DDR+0.3.

Anyway, I decided to continue overclocking with just two sticks instead of four.

So far I have had minimal problems - one BSOD and two fails of Prime95.

I am upto the following:
Q6600 G0 @ 3204mhz
2x1Gb DDR800 @ 712Mhz 5-5-5-18

FSB : 356Mhz
Performance Mode: Standard
DRAM Multiplier : 2.00B
DDR Overvoltage : Normal (1.8V)
MCH Overvoltage : Normal
RAM Speed : 712Mhz
RAM Timing : 5-5-5-18
CIA2 : Disabled
C1E + EIST : Disabled
System Voltages : Manual (CPU Voltage 1.28 [one step up from 1.28750 to 1.29375])

I ran this exact same configuration EXCEPT the CPU voltage was stock at 1.28750 (registering as 1.23-1.25 in Everest 4.6) and Prime95 failed after 3 hours.

I have put the voltage up one step and Everest now says it is 1.25-1.28

The cooler temps are excellent. I know I should calibrate RealTemp but I haven't done this yet as it sounds a bit confusing.

Stock HSF 2.4Ghz under load: 52C (CPU) 52-58C (cores)
Stock HSF 2.7Ghz under load: 57C (CPU) 61-67C (cores)
Xigmatek 2.4Ghz under load: 38C (CPU) 37-46C (cores)
Xigmatek 2.7Ghz under load: 39C (CPU) 42-47C (cores)
Xigmatek 3.0Ghz under load: 40C (CPU) 44-48C (cores)
Xigmatek 3.2Ghz under load: 44C (CPU) 47-51C (cores)

Ambient temp - 16-20C (winter time here)

Does this sound plausible at 3.2Ghz to have almost stock voltage?

Could my RAM be being difficult with the B (333mhz) strapping - should I loosen it to D (400mhz) or something?

Is there any way I could get 4x1Gb sticks working do you think (even with loose timings)?

I am thinking that I will prob just go to 3.4Ghz and leave it there - what CPU voltage is sensible for this?

More about : overclock cpu voltage ram question

a b K Overclocking
a b à CPUs
July 17, 2010 12:48:56 AM

if your ram is set to 1T change it to 2T ( could b "n" instead of t ) and see what happens.. the core 2 i have found doesn't like 1t with 4 slots populated.. it could have been my board, but it's worth a shot
July 17, 2010 4:37:55 AM

Cheers for that, it is at 2T.

I am trying with the following now (asterisks are what I have changed from a previously stable test)

4x1Gb *
FSB : 356Mhz (3204Mhz CPU)
Performance Mode: Standard
DRAM Multiplier : 2.00D *
DDR Overvoltage : Normal
MCH Overvoltage : +0.1v *
RAM Speed : 712Mhz
RAM Timing : 5-5-5-18
CIA2 : Disabled
C1E + EIST : Disabled
System Voltages : Manual (CPU Voltage 1.28 [from 1.28750 to 1.29375])
Related resources
a b K Overclocking
a b à CPUs
July 17, 2010 2:38:12 PM

ok so you added ram, increased mch v, and dram multi. have you run memtest on the ram at stock settings to verify the ram is not bad? also have you made sure your ram is set correctly for timings and voltage?
July 17, 2010 2:51:50 PM

Hiya - yeah I ram memtest for 16 hours on the first 2 sticks when I got them (2.5 years ago) and the second 2 sticks when I got those (2ish years ago) - then all 4 sticks together.

I also had this big thread on the corsair forums where we determined that despite passing memtest & being 'stable' the occasional blue screen was actually down to running 4x1gb & 1066 on a GA-X38-DQ6 without any extra juice to the MCH (even with +0.3v to the RAM)

Also despite both being PC8500 1gb dominator sticks - 2 are version 2.1 (which need 2.1v) and 2 are version 4.1 (which need 2.15v) - annoying!

Anyway - long story short I switched to MCH+0.1v and kept DDR+0.3v and changed to 800mhz@4-4-4-12 (strap 3.00A) and everything was rock solid.

But it must never have been *really* rock solid I reckon due to prime95 failing with round-checking on at stock settings with the new cooler


I have just finished 10h of prime95 blend testing with 4x1Gb @712Mhz (Strap 2.00D) and I am going to try 854Mhz (Strap 2.40D) and up the juice on the ram from stock (1.8V) to +0.3v (2.1v) but keep the timings at 5-5-5-18 and hope that that works as a next step!
a b K Overclocking
a b à CPUs
July 17, 2010 3:31:13 PM

that is a big jump for the ram,,, i wish you luck and keep us may get up to 900 if th ram is good and the memory controller can handle it. remember whene populating 4 slots, you are stressing the controller as well as the ram
July 17, 2010 8:57:01 PM

Hi there,

SO far so good - 5.5 hours of prime95 blend + unigine heaven looping.

Did you mean a big jump for the ram for speed (712->856mhz) or for the voltage (1.8->2.1v) ?

The MCH temps topped out at about 35C for this run of tests.

In the height of summer before overclocking (Stock FSB 266, default strap and 1066mhz 5-5-5-15) the four sticks would cause the MCH to hit almost 60C (which is why I put an antec spot cool on it)
a b K Overclocking
a b à CPUs
July 17, 2010 11:05:38 PM

i meant 712-856 may have to increase voltage to the ram
July 17, 2010 11:12:10 PM

Prime95 Blend + Unigine for 5.5 hours seems ok - though I'll do some more testing later.

Here are some preliminary benchmarks which make for interesting reading.

So My system:

Q6600 2400Mhz with stock cooler
4x1Gb Corsair Dominator PC8500 800Mhz@4-4-4-12
FSB 266
Memory strap 3.00A
MCH +0.1v
DDR +0.3v
Performance mode: Extreme
EIST + C1A: enabled
CPU core voltage: 1.28750 (Reported in windows as 1.23-1.25)
HIS Radeon 5870 (Stock)
Silverstone OP1000W

Q6600 3204Mhz with Xigmatek hdt-s1283
4x1Gb Corsair Dominator PC8500 854Mhz@5-5-5-18
FSB 356
Memory strap 2.40C
MCH +0.1v
DDR +0.3v
Performance mode: Standard
EIST + C1A: disabled
CPU core voltage: 1.29375 (Reported in windows as 1.25-1.28)

Stock idle: 27C (CPU) 31-36C (cores) 32C (MCH)
Stock load: 52C (CPU) 52-58C (cores) 36C (MCH)
OC idle: 26C (CPU) 28-32C (cores) 27C (MCH)
OC load: 45C (CPU) 48-54C (cores) 38C (MCH)

3DMark Vantage Performance:
Stock: 12231
OC: 14689 (19%+)

Stock: 13583
OC: 17756 (31%+)

Unigine Heaven 1680x1050, DX11, 4xAA, 16xAF, Tessellation normal:
Stock: 754
OC: 759 (0%+) - this actually maxes the GPU

Lost Planet Max Detail 1680x1050 4xAA:
Stock: 70.4fps
OC: 78.4fps (11%+)

Crysis Warhead Enthusiast 1680x1050 0xAA:
Stock: 39.1fps
OC: 42.1fps (8%+)

Far Cry 2 Ultra 1680x1050 4xAA:
Stock: 70fps
OC: 75fps (7%+)

So I guess the old saying that benchmarks don't mean as much as gaming is true :-)
July 17, 2010 11:13:02 PM

Hard Line said:
i meant 712-856 may have to increase voltage to the ram

Oh yeah I did - I went from stock MCH and Stock RAM to +0.1v MCH and +0.3v RAM (giving 2.1V on the ram)
a b K Overclocking
a b à CPUs
July 17, 2010 11:26:17 PM

oh. ok... sounds like you have gotten your system stable if you still have problems, come back and we will help you out
July 18, 2010 3:46:51 AM

Thanks for letting me bounce ideas!

The thing that has surprised me the most is how little extra CPU voltage I have had to use to get a 33% overclock.

I am going to run it at these settings for a while & see how it goes before deciding whether to try for 3.4ghz