Date:
Sunday , February 08, 2004
Author:
Kyle Bennett
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Overclocking the Prescott 2.8E

Our first over-the-counter Precott CPU yields different results on different boards and the overall results end up being better than we predicted.

Introduction

If you have happened to have been asleep all of last week and missed Intel's introduction of their new CPU, here is a link to our article that covers the technology and performance the 3.2GHz Prescott part showed. For the enthusiast, knowing the technology behind new products is surely a need, but paying for flagship processors is generally not something we do. We are always looking for an investment that we can push beyond its specified limits, gaining performance and having a bit of fun in the process. Intel was kind enough to launch Prescott core CPUs ranging from 2.8GHz to 3.4GHz last week. With help from Azzo Computers, we were able to take delivery of a real-world 2.8GHz Prescott just like one you would buy. It is these CPUs that we like to do our enthusiast testing with as we rely on them to give us a look at the real world of overclocking.

2.8GHz Prescott CPU

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Above is our Pentium 4 "2.8E." The "E" in the part number designates the CPU as being built using a 90nm process. Default voltage is 1.36V and of course it comes with the noted SSE3 instruction set. It comes in a 478-pin package that we are used to and most motherboard builders are advertising their past i875 and i865 motherboards as being "Prescott Ready" and as you will see below, some are and some are not. This is an OEM processor, meaning that it is sold without retail packaging and only come with a 30 day warranty...which we immediately voided. Its multiplier is locked like other retail and OEM Intel CPUs, with the 2.8E having a setting of "14" (14*200=2800MHz). The multiplier limitation allows us to only overclock the CPU by manipulation of the CPU's Front Side Bus.

While not easily read above on the CPU's heatspreader, the SL specification number on our 2.8GHz Prescott was "SL79K."

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Many enthusiasts use sSpec numbers to identify CPUs that better OC than others. The sSpec also allows you to identify exactly what the CPU is. In this case, the SL79K is the only 2.8E currently shown on their specification page.

sSpec Number Also known as specification number. A five character string (SL36W, XL2XL, etc.) that is printed on the processor, and used to identify the processor. By knowing the processor's sSpec Number, you can find out the processor's core speed, cache size and speed, core voltage, maximum operating temperature and so on.

Motherboards Used

We pulled motherboards we still had here in the office for use in the overclocking. We have been wanting to do some compatibility testing as well, and this allowed us the chance. We did run into some hurdles along the way.

Asus

Our Asus P4P800 and P4C800 motherboards would not operate with our 2.8GHz Prescott CPU. Checking the the Asus website for BIOS updates left us high and dry. Interestingly enough, the P4P800S that is based on the single memory channel chipset, the i848, worked just fine with our Prescott CPU at stock speeds. No BIOS update was present nor needed. We did not use this board for overclocking as it is not really marketed for that usage.

UPDATE: Asus supplied a new P4C800 that did not show the same issues and booted fine with the Prescott CPU. We did not fully test this setup though. Asus explained that they had sent a non-retail sample that did not represent actual product for our review (which we have continually asked every mainboard vendor to never do for years now). Asus never sent the P4P800 motherboard as they committed to even after this many weeks.

ABIT

We used two ABIT boards that we had available. The AI7 and the IC7-MAX3. Both boards passed stock CPU speeds stress tests at 3.2GHz. We were working on stressing these boards before we got our 2.8E so we had days of stress testing done when the 2.8E arrived. All of the motherboards we have used with Prescotts run hotter than we are used to. It is not uncommon to see components on the motherboard at 250F/120C degrees.

The IC7-MAX3 did do something that we have never seen before. If you have noticed, we have used square blocks of plastic foam to elevate our boards for years now while we are testing them. The IC7-MAX3 got so hot that it actually melted the plastic block into a liquid form.

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What you are seeing above is the plastic stringing and cooling as the board was pried loose from the block. Amazingly enough though, cutting off the motherboard circulation of cool air did little to hamper its stability. It ran for more than two days in very adverse conditions.

MSI

We tested one MSI board, and that was the 865PE Neo2. This is a retail product that we purchased and never got around to reviewing although we did do a ton of testing with it. With the latest BIOS update, it handled our 2.8E like a dream, running 100% stable and with no bootup or CPU identification issues. It, like the ABIT and Asus boards, runs very hot with a Prescott CPU.