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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Furen - Wednesday, November 30, 2005 - link
It's not supposed to compete against the 3800+ (But it would have been nice if it could match X2s clock-for-clock, at least, since X2s will hit 2.6GHz soon enough) and it does very considering its power consumption.I must say that it looks like 90nm dual-core Turions will be a very good match for these though (which I still dont think they'll hit 35W max power draw), since Yonah on a mobile chipset only uses 25% less power than a "high-voltage" X2 on a desktop chipset.
fitten - Wednesday, November 30, 2005 - link
18% less power at idle and 33% less power under load supposedly with the same video card, HDD, and all of that (they didn't actually reiterate the test system configurations, just said they were the same and were the same as configured in a different article).Remember... the board tested with Yonah was a desktop version board, not a laptop configuration AND both the Yonah and the board it was on were pre-production test boards. It used the 945G chipset but that doesn't mean that the board was designed in any way like a laptop board. Of course, all of the numbers (performance and power) are subject to change (can be up or down) when Yonah and boards are in production.
I wish the Yonah would have been faster, too. It does well in some areas (nearly equaling the X2 4200 which is 200MHz faster clocked) but others it seems to fall down. It looks like the FPUs weren't beefed up enough and it still isn't up to par main memory wise as the Athlon64s.
Carfax - Wednesday, November 30, 2005 - link
Please post some overclocked scores!bigtoe36 - Wednesday, November 30, 2005 - link
AnandPlease lower the multiplier, run 200fsb with the ddr2 in 1:1 mode and give us a true apples to apples comparison against X2.
EIST should work with clockgen in windows if the bios is poor on your board.
Thanks
Beenthere - Wednesday, November 30, 2005 - link
As other PC industry folks have already stated, Yonah, aka YAWNER, is too little, too late and not worth even bothering with. When Conroe and friends arrive, AMD will have already released faster, cheaper X2 CPUs so Intel is still 2 years behind and loosing ground. Why would anyone buy an obsolete, under-performing CPU that requires a new Mobo? Makes no sense.Calin - Friday, December 2, 2005 - link
No, they are fine. They are as fast as the X2 3800+ processors in almost everything (except heavy non-SSE floating point), and they consume less. Everything depends on the price Intel will ask for them.And I would certainly prefer that Yonah over a Pentium D 830. Why there was no power comparison to the D 830 line too?
DrZoidberg - Wednesday, November 30, 2005 - link
Yonah looks ok for notebooks. I mean its slower than AMD X2 but as a mobile processor, its real competitors are AMD Turion and Sempron and Pentium Centrino not X2.I do hope Intel wont price gorge dual core notebook processors, hopefully they only be slightly more expensive than Dothan.
Viditor - Wednesday, November 30, 2005 - link
Actually, it's real competitor is the dual core Turion...I suspect we shall see AMD extend their lead into the mobile sector this next year.
I must say that I had one dissapointment with this preview...
While Anand finished with power numbers, he didn't tell us how or what they measured. For example, was it the whole system or just the CPU? Did it include the Northbridge numbers for Yonah (since these are alreeady included in the X2)? How does this compare to the numbers from the Turion?
tayhimself - Wednesday, November 30, 2005 - link
Well you suspect wrong, which I suspect, in your case, is quite often. First, there are no dual core Turions on the horizon. Second, AMD is not having much success in that sector because intel's platform strategy is useful for laptop builders. Third, Turion power consumption isnt quite on the same level as Dothan. They will need to move to 65nm before building Turion laptops.
Viditor - Wednesday, November 30, 2005 - link
Sigh...have you ever heard of Google before? It's a wonderful little search engine that would have shown you inumerable articles on the Dual Core Turion being released in early 2006...
Gee...then increasing their marketshare by 75% from Q2 to Q3 was unsuccessful, eh?
If someone could translate this for me, I'd be happy to respond...