The introduction of Core 2 Duo about a month ago delivered a new processor with about a 25% improvement in performance over the fastest chips in the market. The top-line X6800, running at 2.93GHz, was the most flexible of the new processors, with completely unlocked multipliers up and down. This allowed settings like running at a 13x multiplier (stock is 11x) at 277 FSB (3.6GHz) at default voltage - the result of the incredible head room exhibited by the new Conroe processors.

Intel Core 2 Processors
CPU Clock Speed L2 Cache Price
Intel Core 2 Extreme X6800 2.93GHz 4MB $999
Intel Core 2 Duo E6700 2.66GHz 4MB $530
Intel Core 2 Duo E6600 2.40GHz 4MB $316
Intel Core 2 Duo E6400 2.13GHz 2MB $224
Intel Core 2 Duo E6300 1.86GHz 2MB $183

Unfortunately, the X6800 costs $999 which is way out of the budget range for many buyers - and it's even more at retail right now due to demand and availability, with the best price we're currently tracking at $1150. The good news is the lowest-priced E6300 outperformed every previous Intel chip. Compared to AMD the E6600 outperformed every AMD processor, and costs $364 to $433 compared to the $825 to $950 for the AMD top-line FX-62. (Almost all of the Core 2 processors are being marked up 10% to 20% at retail, though we expect prices to drop over the coming months.)

So is there a catch? The answer is yes and no. The X6800, as stated, is unlocked up and down, allowing the flexibility to do anything you wish with the outstanding head room of the Core 2 Duo architecture. The rest of the Core 2 Duo chips are hard-locked up and down, which greatly limits the flexibility of the head room which often runs 1000MHz, 1500 MHz, or more - depending on the CPU and motherboard. You could only access this extra power at the stock multiplier. This is actually a big negative compared to AM2 processors, where all chips are at least unlocked down.

ASUS has a history of incredible creativity in their mainstream motherboards. Those who recall the P865 Springdale will remember ASUS was the first to implement the "875 only" PAT speedup on the mainstream 865 - making the 865 just as fast as the more expensive 875. On the 925, where Intel had implemented a clock lock, ASUS was the first to find a way to break the clock lock and unleash extended speeds on their 875 motherboards. With this history in mind, it should not come as a surprise that ASUS has just introduced some very creative thinking in a new BIOS for their 965P chipset P5B Deluxe motherboard.

The new 0507 BIOS for the P5B Deluxe, dated 8/10/2006, has two new and exciting features:
  1. Provide better maximum overclocking.
  2. Add the ability to adjust the multiplier of most Conroe CPUs even if they are not Extreme Edition.
The P5B reached about 362x10 in testing for the Conroe Buying Guide: Feeding the Monster. This provides a baseline for comparing the new BIOS to previous results.

Even more exciting is that ASUS says they have found a way to unlock up or down most Conroe chips. This will be a significant new feature that is highly desired by many Core 2 Duo buyers. It didn't take but a few minutes for us to get the new BIOS flashed and a Core 2 Duo chip mounted to check this out.

A pattern has been developing for some time in test results from Core 2 Duo chips. The 2MB Cache chips, the E6300 and E6400, are generally overclocking a bit better than the 4MB E6600, E6700, and X6800 chips. Since performance of the 2MB is a bit lower than the 4MB cache at the same frequency, this means you can make up for some of the 2MB cache deficiency with the ability to run at a faster speed. With this in mind, testing was performed with all 4 of the Core 2 Duo chips that are multiplier locked - the 4MB E6700 and E6600, and the 2MB E6400 and E6300.

E6700 & E6600 – 4MB Cache
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  • HammerD - Wednesday, September 06, 2006 - link

    Well as others have said this is an interesting article, but it is far from complete. As an owner of a P5B Deluxe, Conroe 6300, and that "expensive" OCZ ram myself, I am not able to overclock anywhere NEAR what this article claims with my "retail" B2 stepping Conroe.

    You should definately post full system specs including what power supply was used, what video card, all bios settings, hard drive, voltages, tweaks, exact brand/type/config of memory, etc etc. Most AT articles have a "Test Setup" page that describes this, but this article does not.

    Also I don't think "SuperPI" is a good indicator of 100% system stablity. I can overclock pretty high like 400MHz FSB too, to get my 6300 upto 2.8GHz, boot into Windows XP, and SuperPI passes, but Prime95 fails.

    The highest completely stable overclock I can get on my P5B Deluxe system is 325x7 = 2.275 GHz with the 6300 Conroe. That is hours and hours of Prime95 passing.

    This is a good article, just needs to be completed.
    Reply
  • isvaljek - Sunday, September 03, 2006 - link

    Does this mean E6300 can run at 3.5GHz with FSB:RAM 1:1 with plain 533MHz PC4200 RAM? Reply
  • LordX2 - Wednesday, August 30, 2006 - link

    Hey all, this is probably the wrong place to post this, but is the 975X chipset going to be upgraded to allow multiplier unlocking?

    Most importantly though, does anyone know if the 7950 G
    X2 video card will work with the P5W-DH Deluxe? I called asus and they said they dont know lol... does anyone here have HANDS on experience with a 7950 gx2 working with a P5W-DH Deluxe?

    Any info or links would be greatly appreciated!
    Reply
  • JyriT - Wednesday, August 30, 2006 - link

    I've got the P5B, E6400 and DDR2 800. Does it sound like a good idea to set the memory/FSB for 400 MHz and processor for 6x400 MHz? Reply
  • KHysiek - Sunday, August 27, 2006 - link

    Why tehere is no info about what memory modules were used and at what parameters.
    I've read here thst i t was some superxpensive OCZ mem.
    If it's true what sense is buying mainstream mobo, cheaper model of CPU and Superexpensive memory?
    Reply
  • gilahacker - Saturday, August 26, 2006 - link

    Anandtech has done an excellent job showing what is possible with standard cooling solutions, but I'm curious as to how high these chips could really be cranked (i.e. with water cooling). Perhaps only the EE could really benefit from this?

    Provided the price keeps tumbling on these little beauties and their associated parts (mobo/ram/etc.), I think I'll be putting together a new high-end desktop with an E6600 (or higher, depends on the price) and I'd like to do some water cooling for a few reasons, mainly:

    1.) noise level
    2.) stability/overclockability (did I just make up a word?)
    3.) it's f-ing cool (no pun intended)

    If I'm understanding correctly, lowering the multiplier and increasing the bus speed should produce a much faster system overall compared to just increasing the multiplier as you're also increasing your memory speed right? So a system overclocked to say 3ghz (for number's sake) using a lower multiplier and higher bus speed would be faster than a system overclocked to 3ghz using only a higher multiplier?

    And on chips that unlock "up" for the multiplier, you could still increase the bus speed for even greater performance right?

    Thanks for any info. Keep up the good work Anandtech!
    Reply
  • yyrkoon - Saturday, August 26, 2006 - link

    Yeah, but going from old school thought. higher FSBs can also mean parts wear out faster (namely the motherboard), I dont know if with memory dividers etc, if this is still the case. Anyhow, this is why I would like to see a detailed overclocking article, these little 'how-to's' all over web, and forums are in-complete, and dont offer really any insight on how this all plays a factor. However, to answer your question, YES, using a lower multiplier, with a higher front side bus, should increase performance, and I can especially see how this could play a factor if you were able to run a 1:1 memory divider. Reply
  • yyrkoon - Saturday, August 26, 2006 - link

    err sorry, meant to say lower multiplier with a higher FSB should improve performance, as long as the CPU speed remains the same. Reply
  • zemane - Saturday, August 26, 2006 - link

    Next year's BIOS (seen on page 1)

    quote:

    The new 0507 BIOS for the P5B Deluxe, dated 8/10/2007, has two new and exciting features:


    Reply
  • Gary Key - Saturday, August 26, 2006 - link

    That is why the bios is so special, it is a year ahead of its time. LOL... I will get that changed and actually the 0605 bios is out now. Reply

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