AnandTech: ASUS P5B: New BIOS Adds Unlocking & Improved Overclocking

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:

Provide better maximum overclocking.
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.