Overclocking Potential of Intel's 65nm Processors

The biggest question on our mind was how far we could push Intel's new 65nm processors. Keep in mind that these are still early 65nm samples and the actual launch is still some time away, so overclocking potential could very well improve beyond what we report here. That being said, the launch of Cedar Mill and Presler is quite possibly the last time that we will be able to hit extremely high clock speeds for a very long time on Intel processors, so we were quite curious.

First up was Cedar Mill, which we had running at 3.60GHz at 1.300V by default. Our first test was to see how far we could get it without increasing the core voltage, and the best that we could do there was 4.25GHz (250MHz x 17.0).

Our next test was to see how high we could push the 3.60GHz processor on a stock Intel HSF. The result ended up being 4.50GHz at 1.4125V, using a 250MHz FSB and the chip's default 18x clock multiplier:

We were able to POST at speeds as high as 4.73GHz, but even after increasing the voltage significantly, we couldn't get the chip to be stable. A 3.60GHz Prescott can generally get as high as 4.2GHz, so we achieved a bit more headroom at 65nm.

Next up was the dual-core Presler, which ran at a stock speed of 3.40GHz at 1.300V. Without increasing the core voltage at all, we couldn't break 3.5GHz on our Presler sample, so we went straight to bumping up the voltage. At 1.3625V, we managed to get Presler up to 4.25GHz (250MHz x 17.0), which was a fairly reasonable boost. The best overclocks that we have seen on a Smithfield based Pentium D have taken the chip up to 3.9GHz, so breaking 4.0GHz on a dual core Pentium D is pretty impressive (especially with twice the cache).

It shouldn't be too surprising that Presler and Cedar Mill overclocked to reasonably similar levels, given that Presler is nothing more than two Cedar Mills on a single package, rather than a physically larger die.

Introducing Cedar Mill and Presler Power Consumption of Intel’s 65nm Processors
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  • semo - Tuesday, October 25, 2005 - link

    quote:

    NetBurst is dead, as are the days of Intel's 31+ stage pipelines...
    it is awfully tricky typing with left hand while spinning underpants with right hand and jumping up and down at the same time
  • yacoub - Tuesday, October 25, 2005 - link

    I'm waiting until I can pick up a 5.0GHz dual core Intel chip with an 8MB L2 cache and frickin' flames painted on the sides of it.
  • Griswold - Wednesday, October 26, 2005 - link

    With sidepipes too! Pardon me, heat-sidepipes!
  • mlittl3 - Tuesday, October 25, 2005 - link

    For all of you asking about AMD's future, here is a link to an article with leaked AMD processor pricing guide (could be fake).

    http://www.avault.com/news/displaynews.asp?story=1...">http://www.avault.com/news/displaynews.asp?story=1...

    Bascially, one can tell from the memo that the FX-60 will probably be dual core 2.8 GHz CPU (increments of 5 instead of two now to match Opteron plus two cores means +5 instead of +2) and there will be a dual core 2.6 GHz called 5000+. All of the single core Athlon 64s will be reduced in price to be below all the dual cores (except the 4000+ will be a little above the x2 3800+). All the semprons will be below single core athlons except the 3400+ sempron will be a bit above the 3000+.

    Have fun dreaming of what you are going to buy. From the looks of things, AMD will be phasing out single core high speed processors sooner than we think. That means no 3.0 GHz in '06 Q1. :(
  • stephenbrooks - Tuesday, October 25, 2005 - link

    Uhhh... I think the FX-60 is actually a 3.0GHz DDR2-667 single core part. Looks like the FX-59 3.0GHz DDR-400 got shelved, presumably to avoid confusion having two at the same clock speed but different memory.

    X2 5000+ ought to be 2.667GHz dual core on DDR2-667.

    That is, if you believe this: http://www.c627627.com/AMD/Athlon64/">http://www.c627627.com/AMD/Athlon64/
  • JarredWalton - Wednesday, October 26, 2005 - link

    Not your fault, but I don't believe they have the details correct on that site. In fact, I'm almost sure of it.

    333 MHz CPU bus speed seems questionable at best to me. We might get that, but right now even the best 939 motherboards get flaky above 300 MHz CPU bus, and DDR2 isn't going to fix that. I'm inclined to think that AMD would go with a 266 bus instead, but really I don't think they'll even do that.

    Why? Simple: RAM speed on AMD systems is really independent of CPU bus speed. So, you can have a 200 MHz CPU bus with 1000 MHz HyperTransport, and the RAM can run at anything you want! (The RAM speed is derived from the CPU speed and has nothing to do with the CPU bus speed.) The 1000 MHz HT bus listed leads me to believe AMD will stick with a 200 MHz base CPU bus speed and 5X HT multiplier. The only change will be that instead of a CPU/12 divider on the 2.4 GHz chip, they'd have a CPU/8 divider. (That would actually result in DDR2-600, but since CPU/7 would give DDR2-686, they'll have to stick to the lower speed.)

    Given that information, my guess is that the X2 5000+ will actually be the same as the X2 4800+, only with DDR2-667 support on socket M2. In other words, my bet right now is that M2 5000+ will be 2.4 GHz. It makes sense: the socket shift will almost certainly come with a speed increase, and so AMD will have different model numbers for the new sockets. It will basically be like the past: 2.2 GHz 754 is a 3200+ while the 2.2 GHz 939 is a 3500+.
  • stephenbrooks - Wednesday, October 26, 2005 - link

    Yeah the guy changed his roadmap just this afternoon! Sorry about that.

    A shame really, I'd have liked to see the higher bus, but as you say it's a big jump from the current technology.
  • mlittl3 - Wednesday, October 26, 2005 - link

    I agree with Jared about the FSB. The FSB is not the same on the Athlon 64's as the Athlon XP's and the Pentium 4's, Stephenbrooks. You can't just go to 333 MHz to match the ddr2 memory speeds. The FSB if you can even call it that will always be a HT bus running in half or full duplex mode and will probably stay a multiple of 200 for awhile. Just my guess.

    But I disagree with Jared about what the chips are in the leaked pricing memo. If it is a true memo, then I think all processors on it are Socket 939 (no DDR2). It says Q1 '06 and I think the new sockets from AMD are not due until March. We are seeing the last of the Socket 939 processors and I think they are trying to move to all dual core similar to intel. Dual core on the FX processor (2.8 GHz giving 5 increment model numbers like the opterons) and a 200 MHz bump on the X2 5000+ to 2.6 GHz. We were all expecting a 2.6 GHz dual core part but a 2.8 GHz is a little iffy without the 65 nm shrink to keep things consuming less power.

    Oh well, only time will tell.
  • JarredWalton - Wednesday, October 26, 2005 - link

    Oh, I didn't look at the AV link, mlitt, so I wasn't referring to that information. I'm still wondering what the 5000+ will be. If you look at the clock speeds and past performance, Toledo at 2.6 GHz is almost certainly a 5200+, while Manchester at 2.6 GHz would be the 5000+.

    2.6 / 2.4 = 1.08333 (8.33% speed increase)
    4800 * 1.08333 = 5200
    4600 * 1.08333 = 4983

    I'd guess we'll see a couple 2.6 GHz socket 939 X2 chips in early 2006. I could be wrong on the socket shift and AMD will just use the same names for the same speed, but the 754 to 939 shift indicates that they like to take advantage of faster platform performance by increasing the model number, so I really don't think they'll do that. If M2 chips are 5% faster than 939 chips, there's no way the marketing department will let that pass by without some hype. :) Besides...

    4800 * 1.05 = 5040
    4600 * 1.05 = 4830

    If the 5% guess is correct, I expect a 200 point model number change. Though it would be nice if they actually didn't overlap numbers, so in the above two instances they could call the 2.4 GHz 512K/1MB M2 chips the 5050+ and 4850+. Wouldn't it be great to actually have less obfuscated performance for once?
  • mongoosesRawesome - Tuesday, October 25, 2005 - link

    I really appreciate this article. Curious as to how you secured these chips without having to sign an NDA.

    AMD's A64s need to be able to reach 3.0 GHz in order for them to stay competitive with these new 65nm intel chips on the overclocking front. While some of their venice chips are definitely reaching those speeds, especially with a decent voltage bump, most don't quite make it. I expect that by the time these 65nm chips come out though, a 3.0 GHz OC on a 3800+ dual core system should be the norm. Competition is good, now we just need intel to lower their price on their motherboards and not attempt to restrict OCing on their motherboards chipsets.

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