Intel's Pentium M Desktop Part II: ASUS' Pentium M to Pentium 4 Socket Adapterby Anand Lal Shimpi on March 24, 2005 1:31 PM EST
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Before reading this article, be sure to read our first Desktop Pentium M investigation, as we will not be revisiting any of the discoveries/conclusions in that article.
At this year's Spring IDF, Derek Wilson, Johan De Gelas and I all sat across the table from Intel's Justin Rattner and asked him a question that had been on our minds ever since Prescott's introduction. The question went something like this:
Recently, Intel has shifted their focus away from ramping clock speed to increasing performance through other means such as exploiting TLP (Thread Level Parallelism). Given that Intel's direction today seems to be in sharp contrast to the direction of the NetBurst architecture and especially the direction of Prescott, were the past five years of microarchitecture improvements and innovations essentially a waste?
Rattner's exact answer encompassed a few items, but the main points were as follows:
1) At the time of Prescott's inception, clock speed is what sold, so clock speed was obviously the top priority; and they did quite well at that.
2) The past few years weren't a waste; after all, research continued in the direction of the Pentium M while all of the work on Prescott and Tejas were being done.
The second statement was particularly interesting because it was the first time that we received something tangible from Intel in regards to this question. Clearly, significant elements of future Intel desktop processors will be derived from the Pentium M architecture, but as we saw in our first desktop Pentium M investigation, the time for the Pentium M on the desktop isn't now.
As a mobile architecture, the Pentium M can't be beat. That statement alone is something many assumed that we were contradicting in our desktop Pentium M article, but the purpose of that article was to look at desktop Pentium M performance, where we determined that it fell behind. In the mobile world, without significant engineering investment, it is doubtful that the Pentium M will meet its match anytime soon.
On the desktop, we discovered that there were a handful of limitations to the Pentium M's success:
1) 855GME chipset with only a single-channel DDR333 memory controller
2) Expensive motherboards and high total cost of ownership
3) Low floating point/SSE performance
4) Severely motherboard-limited overclocking
The combination of the four items above meant a few things. While the Pentium M was an excellent contender in general use applications, its total cost of ownership was significantly higher than an Athlon 64 that performed similarly. In other applications, the Pentium M simply fell behind the competition for architectural reasons. In those cases, its high price didn't help it out at all either. The saving grace in many cases required overclocking, but the desktop Pentium M motherboards were far from overclocking monsters for those who were interested.
In the end, our stance on the Pentium M as a desktop solution was that it's more of a wait-and-see proposition. If motherboard manufacturers could produce cheaper, better equipped motherboards and if those elements improved performance, then the Pentium M would be worth another look as a desktop alternative.
We hadn't expected such a solution to come around this soon however, but it has, and not in the form that we originally thought it would. Both AOpen and DFI have indicated that they were working on updated motherboards based on the mobile 915 chipset, but that they were still months away. So when we received word that ASUS had a solution to the Pentium M desktop problem, we were caught off-guard. And rightfully so, as their solution is far from just a new chipset...