Yonah vs. Dothan

We didn’t have much time to put together this piece, but at the same time we wanted to present the most complete picture of Yonah as possible, so we went back to our last Pentium M on the desktop article and configured our Yonah system identically so we’d have as close to an apples-to-apples comparison as possible.  Of course it is impossible to use the same motherboard, due to the socket differences we’ve already mentioned, but the rest of the systems are configured identically.  We apologize in advance for the brevity of the benchmark suite, in due time we will present an even more thorough look at Yonah, but for now we are working with what we’ve got.  Also keep in mind that the platform and processor are both pre-release samples, so performance could change, most likely for the better.

With that said, we've got a question and that is: how does Yonah stack up to Dothan?

Unfortunately, our Yonah only runs at 2.0GHz, and our reference Dothan numbers are from a 2.13GHz CPU - so we don’t get the clock for clock comparison we were hoping for, making it even more difficult for Yonah to impress.  Thankfully our first benchmark is clock speed independent as we look at how cache latencies have changed from Dothan to Yonah using ScienceMark 2.0:

   L1 Cache Latency    L2 Cache Latency  
Dothan 3 cycles 10 cycles
Yonah 3 cycles 14 cycles

 

And changed they have indeed.  If you’ll remember from our earlier desktop Pentium M investigations, Dothan’s very quick 10 cycle L2 cache allowed it to be competitive with AMD’s Athlon 64, despite lacking an on-die memory controller.  With the move to Yonah however, the L2 cache latency has gone up a whopping 40%.  While we’re still dealing with a lower access latency than the Pentium 4, this increase will hurt Yonah. 

We’re guessing that the increase in access latency is due to the new dynamically resizable L2 cache that’s used in Yonah.  In order to save power as well as maximize the use of the shared L2 cache between cores, Yonah can dynamically adjust the size of its L2 cache, flushing data to main memory when faced with low demand.  The associated logic is most likely at least partially to blame for the increase in L2 cache latency. 

So Yonah has a slower L2 cache working against it, but two cores and a handful of architectural enhancements working in its favor - let’s see how they stack up in the real world.

First up, we’ve got our business application tests:

   Business Winstone 2004  Communication (SYSMark 2004)  Document Creation (SYSMark 2004)  Data Analysis (SYSMark 2004)
Dothan (2.13GHz) 24.3 129 202 118
Yonah (2.0GHz) 21.6 146 215 138

 

Dothan has a sizeable lead in Business Winstone 2004, which we’ve always attributed to its low latency L2 cache.  Since the benchmark gets no benefits from dual core, and doesn’t take advantage of any of the SSE improvements to Yonah, the advantage is clearly in Dothan’s court. 

The SYSMark tests paint a different picture, with Yonah outpacing the faster clocked Dothan by 6 - 17%.  What’s interesting to note is that in these tests, the performance advantage isn’t exclusively attributable to the advantage of having two cores - Yonah’s architectural advancements are at work here as well. 

The digital content creation tests are where Yonah’s improvements should shine:

   Multimedia Content Creation Winstone 2004  3D Content Creation (SYSMark 2004)  2D Content Creation (SYSMark 2004)  Web Publication (SYSMark 2004)
Dothan (2.13GHz) 29.8 188 255 169
Yonah (2.0GHz) 34.7 264 323 236

 

And shine they do; thanks to a combination of the move to dual core as well as the architectural improvements over Dothan, Yonah shows anywhere between a 16 - 40% increase in performance. 

   DivX   Doom 3  
Dothan 39.7 fps 95.5 fps
Yonah 57.5 fps 93.8 fps

 

The DivX test shows what we’ve pretty much seen across the board from dual core scaling in video encoding, so there’s no surprise there.  Our only gaming benchmark, Doom 3, shows a hazier picture with Dothan on top, and Yonah close behind.  We will investigate gaming performance of Yonah much closer later on.  

What we can walk away from these benchmarks with is an idea of the level of improvement to expect from Yonah, but now comes the real test - how does it stack up against other desktop processors, especially the Athlon 64 X2. 

Same Size, but Twice the Cores Business Application Performance
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  • edwardhchan - Wednesday, November 30, 2005 - link

    For those who care, this is probably the chip that will make it into the Macs next year. Drooling over a new powerbook that dualboots.... Reply
  • bldckstark - Wednesday, November 30, 2005 - link

    I suppose you will be drowning yourself when you start dreaming of a triple boot with the GoogleOS? On Cell processors? With SkyFi wireless bouncing signals off of the moon (system outage during new moon transition)?
    Dreams of vaporware let you down more often than a topless dancer when you run out of ones.
    I do however often dream about my robotically driven car so that I may play PC games from the back seat on my 60" OLED TV during the drive to work. Imagine internet access on the road then. All the mobile PRON. Gives a new meaning to the word carjack doesn't it?
    Reply
  • dougSF30 - Wednesday, November 30, 2005 - link

    and on the next generation process.

    So really, one could say it this way:

    AMD's IMC allows their 90nm DC part with 1/2 to 1/4 the L2 cache to perform better than Intel's new 65nm part running at the same clock speed.
    Reply
  • fitten - Thursday, December 01, 2005 - link

    Only fanbois would say that (or folks who just don't know about computer architectures).

    a) The AMD Athlon64 has a faster FPU than the Yonah. Benchmarks doing heavy FPU will do better aon the Athlon64.
    2) The Athlon64 has more memory bandwidth available to it than the Yonah. While chipsets for Yonah are dual channel, the chip itself still seems to be single channel (like it's predecessors - for power reasons). This configuration does give better performance than all single channel but it isn't as good as all dual channel.
    D) Despite these two disadvantages (there are a few others), Yonah still manages to stay close to the Athlon64 parts on average. Some benchmarks it's actually a little faster and some it's a fair bit slower.

    One of the best unsung things about the Athlon64 X2s is that a single core Athlon64 only benefits marginally in real benchmarks with dual channel memory compared to single channel memory (ignore synthetic benchmarks). The best I've seen is 20% faster but it is typically on the order of 7% faster. This means that adding a second core, which can double the bandwidth requirements to main memory in really bad situations, can be almost completely satisfied by dual channel. Using the best cases above, the benchmark would need 1.20x the bandwidth of single channel, so this same with a dual core would need 2.4x single channel bandwidth. That's only lacking by 20%.

    Compare this to the Pentium4 which gets very large speedups (60% or more sometimes) from dual channel over single channel. Two of those cores doing that would need 3.2x single channel, but dual channel only gives 2.0x meaning that the Pentium4 dual core may have a deficit of 60% of the bandwidth needed to run both cores full-tilt.
    Reply
  • Leper Messiah - Thursday, December 01, 2005 - link

    But what does the above have to do with Yonah's performance. Architecturally, Yonah is far closer to K8 than to netburst. It should have more than enough bandwidth provided with the "667" FSB, esp. if its dual channel. Reply
  • Anemone - Wednesday, November 30, 2005 - link

    I'd agree, the basic core of the A64 chip is quite superior to the P-M, meaning when you take out the cache factor (remember that also applies to programs whose requirements exceed the 2M cache as well so think ahead on that).

    And yes someone mentioned power requirements going up for Merom - which might require a moderating of clockspeeds to keep it in check in the mobile arena.

    Basically for AMD and Nvidia a big opportunity exists here to deliver (and deliver soon) the M2 and take advantage of a very good, but not superb chip from Intel. It remains to be seen if that can be done.

    Yonah is good, and would have been great if it had delivered when originally promised (Aug 05, from very early roadmaps), however it is not stellar. But as an overall mobile platform is is the current best. Kudos Intel.
    Reply
  • dougSF30 - Wednesday, November 30, 2005 - link

    And as far as power goes, Intel admitted that 64-bit would've pushed the power way up on Yonah, so you need to consider that when looking at Yonah TDP vs. X2 TDP. Reply
  • Amagus - Wednesday, November 30, 2005 - link


    I'm assuming the load tests were for both cores being fully stressed. What I would have like to have seen were power numbers on a similarly configured Dothan desktop. That would give us a better idea of how expensive that 2nd core is and how good Intel's 65nm process is.

    -Amagus
    Reply
  • phaxmohdem - Wednesday, November 30, 2005 - link

    Well, I'm fairly impressed with this chip personally. It's definately not the "spooge your pants" object of Techno-Lust many of us were hoping for, but as a man truely impressed with the performance of his Banias Pentium M 1.6GHZ CPU, I can only imagine how awesome that 2.0 Dually would be in a laptop.

    If Conroe can pull off slightly better performance per clock + higher clock speeds + add an integrated Mem/PCIe controller.... We might see some good shiznat in the year to come.
    Reply
  • NullSubroutine - Wednesday, November 30, 2005 - link

    Intel at least has something to offer if you want a decent notebook. I think it all comes down to cost. It probably wont be as equally fast as an AMD dual core Turion, but if it costs alot more, the whole "less power" really doesnt sell me on the extra money I would have to spend for the entire Intel setup.

    The product is a decent product, it doesnt blow you away, but it is something that you can get in a new system and not be disappointed (unless you encode/decode). I personally plan to buy a dual core laptop sometime at the end of spring, if the price is right, then it might be what I am getting (unless they produce that Monroe by then).
    Reply

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