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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lee1026 - Wednesday, November 30, 2005 - link
They still can't beat the A64 3800+? sad, intel, sad.Pythias - Wednesday, November 30, 2005 - link
Graphs I looked at, it appeared the two were neck and neck. And the yonah cosumes less power.Darth Farter - Wednesday, November 30, 2005 - link
well, what about the RAM power consumption difference... is this censored or something?Yonah's 1.8V DDR2 ram opposed to the Athlon X2's 2.6V DDR ram
if the reviewer really measured "Total System Power" this will factor in... the same reason why the Pentium M is still king of Battery Life on mobile platforms...
When Socket M2 arrives Q2 2006 it could prove better for performance and less for power requirements again.... and without being transitioned to 65nm process yet.
anyway, this is not cpu isolated and therefore I'd suggest just mentioning it includes the worse DDR power consumption (apples to apples) before the community blames the cpu only like in the comments here.
(btw, if there would be any way to isolate the cpu power usage only without motherboard and ram I would really like to know. (I thought I saw something like that on overclockers.com a few moths back.)
anyway could my point matter on the graphs on last page Anand?
coldpower27 - Wednesday, November 30, 2005 - link
This is the price you pay for having an On Die Memory Controller, Intel can adopt new memory technologies quciker then AMD can as they don't need another revison of a CPU plus a Socket change due to the memory controller, this is the price AMD paid to get the added performance, and reduced power cosumption of having the memory cnotroller on Die and not needing a Northbridge. This is AMD's choice and they have to live with the consequences of this choice.Zebo - Friday, December 2, 2005 - link
Nevermind they did change thier socket.coldpower27 - Sunday, December 11, 2005 - link
I think they wanted to make sure that only the i945M Chipset series is compatible with the Dual Core Yonah and not run the risk of people sticking these into older i915M and the currently available desktop Pentium M boards.This is a move for profit of course, as Intel wants to sell their new i945M chipsets as a Centrino bundle with Yonah.
nserra - Wednesday, November 30, 2005 - link
AMD 64 2.0Ghz at .13 at full load does 68WAMD 64 2.0Ghz at .09 at full load does 43W
AMD 64 2.0Ghz at .65 at full load maybe ~27W
AMD 64 2.0Ghz at .13 at idle does 19W
AMD 64 2.0Ghz at .09 at idle does 13W
AMD 64 2.0Ghz at .65 at idle maybe ~9W
tayhimself - Wednesday, November 30, 2005 - link
90nm 3800x2 is around 68 W. Take out 8 or so for the northbridge. There is no 130nm x2 IIRCnserra - Wednesday, November 30, 2005 - link
Sorry I forgot to mention, its single core amd processors not dual.Viditor - Wednesday, November 30, 2005 - link
Someone who doesn't know the difference between TDP and power usage...