2007: Where Are The Clock Speeds?

The most significant CPU event in 2006 was, without doubt, Intel's release of Core 2 Duo. This will be followed this year by AMD's equally significant release of K10. With a major release from both companies the world of microprocessors would be rosy indeed . . . if not for the nagging question of clock speeds.

Before Core 2 Duo was actually released in mid 2006 there were announcements that Intel would release 3.2Ghz C2D's later in the year. There were even persistent rumors by Intel enthusiasts that 3.2Ghz chips would be available at launch. The latest roadmaps seem to indicate however that even 18 months later, Intel will still be stuck at 3.0Ghz. This however doesn't seem to have dented the enthusiasm of the Intel faithful who were certain that 3.2Ghz chips would be available before the end of 2006 and that at least 3.4Ghz chips would be available before the end of 2007. Most have now simply resorted to chattering about 45nm (Penryn). Supposedly, Intel 45nm is going to allow phenomenal speeds at low power draw. And, these eager souls are hoping fervently that Intel will somehow be able to release 45nm in Q3 07, presumably to compete with AMD's K10. However, Q4 07 looks to be the earliest for 45nm from Intel and there is as yet no indication of higher clock speeds. AMD, not to be outdone, seems equally determined to deliver sub 3.0Ghz clock speeds. AMD gives no indication of getting faster than 2.9Ghz with dual core K10 on 65nm and only 2.5Ghz with quad core K10 in 2007.

So, where are the clocks? Why are AMD and Intel unable to keep increasing clock speed with 65nm and push through 3.0Ghz? One consideration is that AMD has had a history of second wave clocks. For example, the highest clock achieved on 130nm exceeded the initial clock speed of 90nm. And, the high clock on 90nm exceeded the initial speed for 65nm. If this pattern is followed then it would be logical that AMD could reach a higher clock on 65nm by the time 45nm is released. Perhaps this will be the case. The picture is much less clear with Intel since Intel has almost no track record of one architecture on multiple processes. The only crossover has been Smithfield/Presler. With these two we see no evidence at all of second wave clocks. While Smithfield topped out at 3.2Ghz on 90nm, Presler launched at 3.6Ghz.

This has, of course, happened before. In late 2002 Intel was stuck at 3.0Ghz while AMD was stuck at 2.0Ghz. AMD did manage in early 2003 to bump the Barton K7 up to 2.2Ghz and, at about the same time, Intel bumped the Northwood P4 up to 3.2Ghz. Intel eventually managed 3.46Ghz with Northwood on 90nm with its Extreme Edition in 2004. However, it certainly looks now like the clock ceiling has returned with both Intel and AMD stuck below 3.0Ghz. I suppose AMD enthusiasts might point out that AMD did have increasing clocks and only recently hit 3.0Ghz with FX-74 and 6000+ (on 90nm). The problem is that we see no indication of clocks beyond 2.9Ghz on 65nm during all of 2007 and up to Q2 08. Strangely, none of the Intel enthusiasts seem to be discussing the lack of a 3.2Ghz Conroe. I suppose if someone can forget that Intel promised a 5.0Ghz Tejas in 2005 and then promised Whitefield with CSI in 2006 then forgetting the lack of a 3.2Ghz C2D clock would be relatively easy. So, ignoring Intel's 18 month span with no clock increases, I suppose it is possible that 45nm really is much better and that Intel could deliver clock rates as high as 3.6Ghz in 2008. However, nothing like this has been indicated yet. And, with a history of second wave clocks I suppose AMD could hit 3.1Ghz on 65nm by mid 2008.

This still does not answer the question though. Since K8 is currently hitting 3.0Ghz on 90nm one would assume that 3.2Ghz would be possible on 65nm. So, why is K10 only hitting 2.9Ghz? I suppose with AMD the problem is the process. Presumably AMD can't soon get over 2.9Ghz without going above 120 watts. Looking at history for AMD this probably matches the release of K8 in 2003. K8 Sledgehammer was released at 1.8Ghz which was roughly equal to the 2.2Ghz Barton K7. This could suggest that the initial 2.3Ghz Barcelona will be roughly equal to the 2.8Ghz Santa Rosa Opteron. The speeds would also parallel the introductory speeds of dual core X2 which were down from the fastest single cores. This also suggests that the later release of 2.5Ghz Barcelona will match the current speed of 3.0Ghz K8. This would put the Q2 08 speed of 2.6Ghz ahead of the current fastest K8. However, it appears that QFX will likewise be stuck at 2.5Ghz. This does seem a bit slow to compete with Kentsfield, however, QFX is a dual socket board. Given Opteron's current near equality with Xeon at the same clock it seems somewhat possible that a dual socket 2.5Ghz QFX could keep up with a dual socket 3.0Ghz Clovertown competitor. However, this is not entirely clear since a true competitor would not use FBDIMM but DDR2 like QFX. So, perhaps Intel could stay ahead of QFX.

And, why is Intel still stuck at 3.0Ghz? In spite of claims that Intel has superior process technology the conclusion would have to be the same, that Intel is unable to clock higher. And, there is no similar history for Intel as there is with AMD. There has simply never been a time when Intel was unable to increase clock speed for 18 months. This is a year and a half with no improvement on the process. Very strange. It is possible that the early results for 45nm were so promising that Intel stopped developing 65nm. This could be the case. I also know that some will claim that Intel has lots of headroom because their chips overclock well. Unfortunately, bulk silicon chips are more prone to failure than SOI chips so Intel has to maintain significantly more margin than AMD. Simply put, careful overclocking by enthusiasts is not comparable to the same speed with a stock heatsink and fan in a standard case in a house with no air conditioning and high ambient temperatures in the summer. Still, I'm sure this myth of headroom will stay alive until Intel moves to SOI as well. If you can conveniently forget the 5.0Ghz Tejas then presumably you can also forget that Dothan, Yonah, and Prescott all overclocked significantly higher than the speeds Intel released. I suppose if Intel fans are guilty of amnesia then AMD fans would be guilty of over-optimism. I've seen people insist that K10 will have a 40% increase in Integer IPC which is purely ridiculous; 20% is much closer to reality.

In terms of single socket in 2007, AMD's competitiveness is somewhat split. For dual core, this would be a 2.9Ghz Kuma versus a 2.93Ghz Conroe. This is a trivial 1% difference in clock, so probably even. However, for quad core this would be a 2.5Ghz Agena versus a 3.0Ghz Kentsfield. This is a not so trivial 20% difference in clock. I'm guessing Intel will stay ahead on this one although I suppose being competitive with the second fastest clock (2.6Ghz) is a lot better than having no quad cores at all. All in all this should be sufficient to halt any gains in share by Intel. Additional gains in share by AMD would then probably depend on other factors like price, availability, and chipset quality. So, it does appear that 2006/2007 mirrors 2002/2003 in several ways. Perhaps we will once again see standard clocks above 3.0Ghz in 2008.