- Back to homepage
- Related articles
  Related articles

Intel Core 2 Performance, Overclocking, Power Usage Review

CPU by piotke @ 2006-07-14

The most anticipated CPU of the year is here! Intel has released the Core 2 which promises amazing performance at low watts. Does it live up to expectations? Find out in this review where we focus on overclocking, CPU scaling and power consumption.

Overclocking

Overclocking - Introduction

The Intel Bad Axe desktop mainboard supports some basic overclocking options. Most important to mention is that the clock speed can be raised with 30%; in steps of 1%. The classic FSB option is nowhere to be found. Besides that there are also the following overclocking related settings in the BIOS:

Enhanced power slope; Enabled / Disabled

Host Burn-in Mode Type; Positive / Negative

Host Burn-in Mode percentage; from 0 to 30 in steps of 1

FSB Frequency override; 533/800/1067

PCI Burn-in Mode; Default / 40.00 Mhz

PCI Exoress Burn-in Mode; Default or from 1001 to 109 in steps of ~1.3 Mhz

MCH Voltage Override; Default / 1.525 V / 1.600 V / 1.650 V / 1.725 V

Front Side Bus Override Voltage; Default / 1.271V / 1.333 V / 1.395 V

That?s a limited selection and with only these there is no way to reach some insane clock speeds. Luckily a larger selection is available but it?s hidden, yet it easily be unlocked.

The OC debug mode lets you change a wider range of settings, it even becomes ?pre-unlocked? with some Core 2 processors. To manually unlock the OC debug mode you need to do the following.

Just above the IDE port you can find a three-pins header with jumper. This is used for BIOS maintenance. But notice, just above that there are three unused solder points. Contact the first two (with solder of conductive paint) and now your entire BIOS is unlocked.

Madshrimps (c)

I found this mod at Xtremesystems.org, where even more modifications can be found. Keep in mind that modding your mainboard will void warranty and might kill your mainboard and/or processor.

With the OC Debug mode unlocked I now have access to:

CPU VID (Vcore) from 1.275 to 1.600 Vcore in steps of 0.025 V

CPU ratio Multiplier; Automatic or manual (from 6 to 60)

Enhanced power slope; Enabled / Disabled

Host Burn-in Mode Type; Positive / Negative

Host Burn-in Mode percentage; from 0 to 30 in steps of 1

FSB Frequency override; 533/800/1067/1333

PCI Burn-in Mode; Default / 40.00 Mhz

PCI Exoress Burn-in Mode; Default or from 1001 to 109 in steps of ~1.3 Mhz

MCH Voltage Override; Default / 1.525 V / 1.600 V / 1.650 V / 1.725 V

Front Side Bus Override Voltage; Default / 1.271V / 1.333 V / 1.395 V

Notice the fact that I have an option to change the multiplier. As an extra feature the retail Core 2 Extreme has its multiplier unlocked, this might be a first for Intel Processors.

You might have noticed that there is not a single memory setting. These can be found in a different part of the BIOS. In the memory section you can change memory clock speeds, timings and memory voltage. Most significant settings are beside all the possible timings:

Memory Frequency; 333 / 400 / 533 / 667 / 800 Mhz

DDR2 Voltage; Automatic / 1.8 / 1.9 / 2.1 / 2.2

Finally there is also a small section that allows you to monitor temperatures, voltages, fan speeds,?

Madshrimps (c)

Overclocking - The real thing !

The X6800 and E6700 were overclocked using the same following the three steps, the E6700 trailed the X6800 overclocking performance by an average of 200Mhz. Not too bad.

1) Using an air cooled Thermalright HR-01 S775 with custom mounted Scythe 120mm fan. Vcore was left at default.
2) Vcore was raised up to a level where the HR-01 could still keep the CPU cool enough.
3) Mounting a custom made phase change cooling which kept the CPU near a chilly 4?C.

Madshrimps (c)

Step 1 At 1.29v default vcore the CPU was stable up to 3.4Ghz, the temperature diode read ~55?C with a very high ambient temperature of 32?C. A ~16% increase, not bad seeing as this is the top of the range Intel Core 2 Extreme.

Step 2 Raising the vcore to 1.36v allowed an additional 100Mhz and temperature rose to ~65?C, a lot of extra heat, without a lot of extra Mhz, total OC at ~19%. An extra vcore bump to 1.48v was needed to make it to 3.6Ghz but the temperatures were too high, surpassing 75?C and the system wasn?t very stable.

Step 3 The phase change brought low CPU temperatures and 3.6Ghz with only 1.36v vcore was stable. It took 1.55v vcore to reach 4Ghz which makes the total overclock ~36%.

The Core 2 is an excellent overclocker if you can keep it cool enough, but even with modest air cooling (the HR-01 with Scythe fan is very silent) the OC margin is remarkable for such early samples. I only tested the higher rated models here, the slower E6600 and below might prove to have a higher overclock-ability.

Let?s take a look at the power usage and the influence of the extra CPU power on the performance ->

All information and graphics contained in Madshrimps are sole property of the Madshrimps crew and may not be reproduced or copied in any manner without written permission from us.