Finally, I set out to essentially repeat my Iteration Set 5 minimizing the VTT with the slightly higher Vcc.
Code:
Overclocking log, Iteration Set 7
Comments: 1.12500V seemed stable, minimizing VTT
DRAM 2.100V
SBCore 1.55V
NBCore 1.37V
Vcc 1.12500V
VTT/Prime95 success or failure
1.250V Failed on core 0 ~ 1 h 3 min
1.280V Failed on core 1 ~ 1 h 0 min
1.310V STABLE 34 h 41 min
Apparently VTT needs to be 1.310V on this system. In any case, those examples should serve to illustrate the method you need to use to attack the task.
To summarize, using a stepwise approach and documenting your runs, you should be able to arrive at a stable system (assuming your hardware can operate at the level you choice). It probably goes without saying that you will need to repeat this process if change your operating conditions (multiplier and FSB).
Temperature Management
An overclocked quad system is often limited by the amount of heat it’s producing, and the ability of the heat sink and fans to dissipate it. If you’re getting high temps, there are a number of things you can do to help. Most of them are hardware related but the first is the single most important non-hardware change you can make:
• Minimize your vcores first (described in the guide above)!
• Ensure good contact between the CPU and Heat sink is a must for efficient heat transfer. A major bang-for-the-buck modification in this regard is lapping the surfaces that transfer heat (the base of your heat sink and the top of your CPU). This involves gently moving the surface along wet/dry sand paper in increasing grits on a flat surface such as a piece of glass. I did both the base of my Ultra-120 Extreme and the IHS (Internal Heat Spreader) on my Q6600 and saw some pretty dramatic decreases in load temps.
It should be noted that lapping your HS and/or CPU will void the warranty. Comparing my stock HS/CPU to my lapped HS/CPU, on average lapping lowered the coolest core by 7 °C and the hottest core by 10 °C. To read more about lapping your heat sink and CPU see these two threads; I have results and pictures of the process:
Lapping Q6600 IHS Lapping the Ultra-120 Extreme
That said my X3360 did not need to be lapped. I’m not sure if Intel is doing this with all their 45nm chips or just the Xeons, but it came from the factory very flat. When I run prime95, the heat spread between cores is 2-3 °C.
• If your NB chipset runs too hot, consider adding a small fan. I put a silent 40x40x10mm fan on my NB HS via a zip tie which lowered my NB temps by ~7 °C on load. Pretty amazing effect for $3 fan and free zip tie
• Consider an upgrade to a more efficient heat sink (like the few mentioned in the beginning of the guide). Remember that a quad core chip will produce about 2x the heat compared to a dual core chip. You really do need to consider using an extreme HS if you plan to overclock a quad.
• Consider an upgrade to the cooling fan on the heat sink to something that has more flow. Most of the larger HS’s will use a 120mm fan. Some have the option for two fans. I think the fastest 120mm fan you can use is around 1600 RPMs. If you have a slower one, you might consider upgrading.
• Reseat your heat sink and make sure you’re using a quality TIM (thermal interface material) such as AS5. Consider rotating the HS 90 degrees if it is designed to do so. I seem to get better contact with my Ultra-120 Extreme when it’s orientated “North/South” than when it’s orientated “East/West.”
• Re-evaluate the way you’re applying the TIM/don’t use too much or make sure you’re using enough. Thermal pastes aren’t all created equally. Some are reported to be better than others. I have always used Arctic Silver 5 on my CPUs (and AS3 and AS1 before that). You can find all sorts of posts out there showing one to be better than another. I’ll leave it up to you to pick one. Again, I like AS5. Here is a shot of my q6600 installed in the MB with AS5 right before I added the HS. It shows the right amount in my opinion given a lapped HS and CPU (which is a thicker line than I used before); the red triangle I drew shows where that tag is on the CPU, remember that on quad core chips, the dies are placed in a different located relative to a dual core, see the
instructions on AS5's website for more on this.
• Use good cable management inside your case. Use twist ties or tie downs to bunch cables and keep them out of the way of airflow.
• Make sure you have adequate airflow inside the case and make sure you’re using a well ventilated case. People often overlook this, but it’s important. Not all cases are designed for good airflow. I have an Antec P182 which is a great design. Make sure you have several exhaust fans and at least one intake fan. 120mm fans move more air than smaller 80mm fans do and also run much more quietly.
You can see that my CPU load temps will increase/decrease as the ambient temperature fluctuates. Have a look at the following thread for details:
Effect of room temp on CPU load temps Controlling vdroop
Remember the vdroop you saw earlier? If you have a P5B-Deluxe (I believe this works on any of the boards in the P5B family actually), you can use a pencil to modify your board to minimize or fully remove this idle-to-load vdroop. Read the following thread if you want to do that:
Get more vcore under load: vdroop pencil mod (pics)
That's it for the guide. I hope you got some good info out of it and are able to successfully o/c your system as a result!