Intel Yonah Performance Preview - Part I: The Exclusive First Look at Yonah
by Anand Lal Shimpi on November 30, 2005 2:50 AM EST- Posted in
- CPUs
Same Size, but Twice the Cores
Obviously the biggest improvement Yonah offers over Dothan is the fact that it’s dual core. But where things get interesting is that thanks to Yonah’s 65nm process, a dual core Yonah die is about the same size as a single core Dothan die - in other words, it costs Intel just as much to make a dual core Yonah, as it did for them to make a single core Dothan.
A major reason the die size didn’t really go up much is because although Yonah has two cores, its L2 cache size remains unchanged at 2MB. Unlike the Pentium D, Yonah’s 2MB L2 cache is not split into two discrete 1MB caches, it is actually one whole 2MB cache that is shared by both cores. This is a very important distinction, as it means that Yonah is far from just two Dothans stuck together.
There are other architectural enhancements to Yonah that will give it a performance advantage over Dothan. Below is an excerpt from our IDF coverage of Yonah, detailing what we know about the new CPU:
Making Pentium M more "Media Friendly"
All of the major performance improvements to each of Yonah's cores seem to revolve around SIMD FP and FP performance, two of the Pentium M's present day weaknesses in comparison to the Pentium 4.
The first improvement is that now all three of Yonah's decoders can decode SSE instructions, regardless of the type of instruction. Improving the decode width of the processor is a quick way to improve performance.
Next, SSE/SSE2 operations (not sure if all can be, but at least some) can now be fused using the Micro Ops Fusion engine of Yonah. At a high level, the benefit here is increased performance and lower power consumption, we'll get into architectural details of why that is when we eventually sink our teeth into Yonah next year.
Each of the two cores in Yonah have also received support for SSE3 instructions much like the Pentium 4 E [Prescott].
And finally there have been some improvements to Yonah's floating point performance, although Mooly would not say exactly what's been done. Curiously, Mooly referred to the floating point performance improvements as specifically made to improve gaming performance. Intel may have grander plans for Yonah than once thought...
The SSE/FP optimizations are all being grouped into what Intel is calling their Digital Media Boost technology, yes the names seem to get worse and worse as time goes on - but at least the functionality should be good.
We started out this article talking about the Pentium M’s shortcomings in digital media applications, and Intel has begun to address them with the architecture of Yonah, but the real question is - how effective have their efforts been?
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coldpower27 - Wednesday, November 30, 2005 - link
It doesn't seem that bad actually at 423US for 2.0GHZ Yonah at launch, it isn't double the 294US, that they are charging for Dothan 2.0GHZ parts now, the price isn't like the double we are seeing on Athlon 64x2.Furen - Wednesday, November 30, 2005 - link
Huh? I'm saying that the FX-60 will probably match the EE edition of Yonah, which (supposedly) will have a 50+ W TDP and will hardly be a "mid-range" mobile chip.coldpower27 - Wednesday, November 30, 2005 - link
These are the leaked pricing sheets from around the web on the launch pricing of Yonah.T2600/ Yonah 2.17GHZ/667/2MB 637US
T2500/ Yonah 2.00GHZ/667/2MB 423US
T2400/ Yonah 1.83GHZ/667/2MB 294US
T2300/ Yonah 1.67GHZ/667/2MB 241US
T means somewhere in 25W-49W TDP
Yonah Extreme Edition would be interesting, either 2.5GHZ/2.66GHZ if on the same FSB speed.
Furen - Wednesday, November 30, 2005 - link
It would have been nice if you'd included Dothan's power consumption just to see whether or not the "Yonah will have a 49W TDP" claims have any validity. I dont suppose you guys are up to testing the current CPU's current draw directly, huh? :)coldpower27 - Wednesday, November 30, 2005 - link
Also you got to keep in mind Yonah will fall in the T category, of processors which is 25W-49W in TDP, with the way Intel measures it. The acutal TDP of Yonah was supposed to be 31W.Furen - Wednesday, November 30, 2005 - link
Yes, but when Intel announced that Yonah was going to fall into that category EVERYONE (most tech sites, heck, even Cnet) equated that to a higher TDP Yonah, which is why it would have been nice to have something to compare it against.bob661 - Wednesday, November 30, 2005 - link
Anandtech is NOT measuring TDP in these tests!!!!!! They ARE measuring what they call "Total Power Consumption". These are two TOTALLY different measurements. AT can only measure power consumed by the ENTIRE computer coming from the wall socket. They can't measure TDP in these tests. It's not the same. It's not the same. Jesus!Furen - Sunday, December 11, 2005 - link
I never said they could measure TDP. I asked if they were willing to measure the CPU's current draw directly, which is VERY doable, though it takes a bit more effort. If you remember that a month or so ago there were news articles published at, basically, all tech news sites claiming that Yonah would have a greater TDP than it was originally anticipated. Though TDP is not necessarily the typical power draw, a higher TDP (compared to another one that is defined the same way) can lead to a higher current draw.I said that it'd be nice if they could include dothan in order to have a CPU with which to do an apples to apples comparison. Try to keep your patronizing comments to yourself if you don't plan on at least reading what you're commenting on properly.
Calin - Friday, December 2, 2005 - link
Nobody can measure the TDP - TDP is the Total Designed Power - and refer mostly to the cooling capacity of the processor package. You will see several models of processors having the same TDP even if their power consumption is certainly different.The Sempron 2500, 2600, 2700 and I think 2800 have the same TDP - even if the 2500 is a 256kB L2 cache part and the 2600 and 2800 have just 128kB L2 cache.
TDP is NOT power consumption!
Calin - Friday, December 2, 2005 - link
Sorry. TDP is thermal design power