ASUS P5B-E: P965 stepping C1 versus C2, Round One

Over the course of the past few months we have heard all sorts of rumors about the Intel P965 C2 stepping and its grandiose performance improvements over the current C1 stepping. There have been previews of its performance on engineering sample boards at various websites touting its overclocking capability along with perceived performance improvements. Our forums and others across the internet are full of questions about the performance of this stepping along with various interpretations of the first test results and the rampant rumors afterwards. These interpretations and rumors include everything from 20% overclocking improvements, memory compatibility fixes, lower power consumption, 10% performance improvements, and a whole host of other claims. Are these interpretations and rumors true or merely urban legends? We will find out in our testing today.

Our investigation into the nefarious underworld of hardware review websites led us to one central theme: the P965 C2 would offer greatly improved overclocking capability. Being inquisitive types we wanted to find out if these rumors were true. After collecting all of our Post-it Notes filled with a night's worth of "internet research facts", we donned our Sherlock Holmes attire, grabbed a sack lunch, and went straight to the source of these chipsets: Intel. The official line was to please check our website for the errata fixes, but we decided to dig a little deeper. After having our sack lunch and hiding our detective attire in order to get past security we were able to privately speak with an engineer about this stepping change. He provided us with the obligatory chart that we hoped would fully explain the changes made in the C2 stepping that will purportedly increase performance, improve overclocking, and bring about world peace. We were excited, as we were about to get some real proof that the performance rumors were true - after all, they were on the internet!



There it is, the official chart from Intel listing the actual changes within the C2 stepping of the P965 MCH. Had we been duped? No way could two minor errata fixes be the cause of all these rumors we had been chasing for weeks. There must be a cover up at the highest levels of Intel... or could it be other competing companies were just spreading FUD (Ed: that's Fear, Uncertainty, and Doubt) in order to cause mass hysteria upon the launch of C2 equipped motherboards? What better way to divert attention away from Intel's latest chipset release and focus it on the upcoming competitor's chipset launch than to release false rumors about the performance and overclocking capabilities of the C2 stepping. This seemed like a brilliant plan: when the general public realized the truth about the C2 stepping they would be disappointed and would once again be searching for the holy nirvana of chipsets that offer extended overclocking capability along with terrific memory performance. These hungry souls would then find solace in competing chipsets like the ATI RD600 and/or the NVIDIA nForce 680i SLI chipset featuring the reworked C55XE.

As our minds raced through this headline grabbing scenario, our patient Intel engineer tired of our day dream session and spoke at last. He informed us that maybe a few minor tweaks were done here and there within the Fast Memory Access section of the C2 stepping, and the source BIOS files are fully optimized for performance now. There is also the fact that the manufacturing process for the P965 has matured quickly with greatly improved yields leading to a larger number of chipsets that overclock well regardless of the C1 or C2 stepping. This all made sense... probably too much sense. We thanked our engineering friend and made plans to sneak up to the General Manager of the Chipset Group's office to search for the truth. Unfortunately, our plot reached an end as we were politely escorted by security to our car, but our investigation was far from over. We were ready to do our best to top DailyTech and get the inside scoop on these persistent rumors!

We decided to contact the motherboard manufacturers and see what they could tell us; after all, they had the C2 stepping and were designing boards around this supposed wonder chip. We contacted several of the motherboard suppliers and asked the same question, "What type of performance increase are you seeing with the C2 stepping over the C1?" They all replied with the same basic answer, "We are seeing minor differences if any at this time." Impossible! The vast number of internet rumors swirling around this chipset revision could not be wrong. There must be a C2 information conspiracy amongst the motherboard manufacturers, or maybe Intel contacted them after our visit and forced them to toe the company line.

After making several promises that could never be kept, we were able to meet with a couple of engineers at ASUS and Gigabyte to discuss this situation; let's call our engineers Tim and Rockson in order to protect their identities. They both agreed that there are very minor differences at best in both the performance and overclocking capability of the C2 stepping when compared to the C1 on the same motherboard. This did not make us happy; yet another "minor performance differences" statement, though we were glad to learn that over time both companies expect to extract additional performance from the Intel P965 chipset as new motherboard designs and BIOS updates are introduced. We felt like we had hit a brick wall trying to find the truth about these rumors and decided to take a break.

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After some well deserved sleep, our heads were finally clear of all the internet rumors and we came to our senses: we made a request for a P965 C2 stepping motherboard. Instead of reading, guessing, or talking about the performance benefits of the C2 stepping we were now determined to actually test it, even if it meant trip expenses that would not be reimbursed. (Ed: Accounting, ignore this boisterous offer!) Instead of requesting one of the new motherboard designs that will only feature the C2 stepping, we asked for a currently shipping motherboard that offers either the C1 or C2 stepping. ASUS happily obliged our requests with their new P5B-E motherboard. This board is currently shipping with the C1 stepping and will switch to the C2 stepping in the near future. ASUS shipped us two production level boards with the only difference being the P965 stepping. Our boards are revision 1.01G and utilize the latest 0402 BIOS.

All tongue-in-cheek sleuthing stories aside, we will review this motherboard in greater detail in our upcoming P965 roundup, along with the 1.02G variant. The new variant features the C2 stepping, additional voltage options for the MCH and DIMMs, and probably a new marketing designation to differentiate the revision levels. For now, we are simply trying to find out whether the P965 C2 stepping makes any difference in performance or overclocking. Our review will compare the performance of each stepping on this motherboard along with some basic E6300 overclocking tests. We will follow up with a look at E6600 overclocking and additional comparisons between P965 steppings on the Gigabyte GA-965P-DS3 in the near future. Now let's take a look and see just how well the P965 C2 stepping performs against its older C1 sibling in the ASUS P5B-E.