Intel Core Duo (Yonah) Performance Preview - Part II
by Anand Lal Shimpi on December 19, 2005 12:55 PM EST- Posted in
- CPUs
Another issue that we had with the first article was that our comparison to the Pentium M was based on using an Intel 865 chipset; more specifically, using ASUS' CT-479 adapter and their P4P800-SE motherboard. While the motherboard itself performs quite well, we wanted a more even comparison between the Pentium M and the upcoming Core Duo processor.
We turned to AOpen and they provided us with their i915Ga-HFS motherboard, based on Intel's mobile 915 express chipset with native support for the Pentium M processor. The biggest difference between our AOpen 915 platform and the 865 platform that we tested back in March? The 915 platform supports DDR2 memory, just like the 945 platform that we used with the Core Duo. Being able to use the exact same memory technology across both platforms removed yet another variable from our comparison, but frankly, it wasn't going to do much to the performance breakdown between the two chips.
AOpen's board worked well during our testing, although we did have the occasional issue where the system would not POST. The issue wasn't readily repeatable, but it did happen a few times during our testing.
The only other quirk that we ran into with the AOpen board was the fact that it features absolutely no legacy ports on its I/O panel. There is support for a single PS/2 port that requires a separate bracket to be installed in your case (provided with the motherboard). Given the prevalence of USB keyboards and mice these days, it's not that big of an issue. We only mention it because the majority of our KVMs in-house are still PS/2 based.
We paired AOpen's 915 board with a Pentium M 760, which is based on the 90nm Dothan core running at 2.0GHz with a 533MHz FSB. So while the FSB speed is slower than the Core Duo that we're testing, the identical clock speed is helpful in a direct comparison between the two chips.
Facebook
Twitter
RSS
103 Comments
View All Comments
Furen - Monday, December 19, 2005 - link
The P6 has two FP units: An FADD unit and an FMUL unit. One of the big weaknesses of the P6 is the fact that the FMUL unit is not fully-pipelined but instead uses part of the FADD unit for FMUL operations. The K7, on the other hand, has three fully-pipelined units, an FADD, an FMUL and an FSTORE.tayhimself - Monday, December 19, 2005 - link
No he's not. AT's hardware reviewers are nublets. One thing to note though, Dothan FPU is better than the P4's hence its gaming performance advantage over the P4 in the old tests that everyone saw. It's likely that Yonah FPU is still the same as Dothan (similar to P3) and inferior to AMD's.saratoga - Monday, December 19, 2005 - link
Actually the FPU on the P4 was tremendously more powerful then Dothan or Yonah. While games do use the FPU, they're not that bottlenecked by it on modern systems. The reason Dothan did so well was because of its large, very low latency L2 cache. This is roughly equivilent to the primary advantage of the K8, a very low latency memory controller.tayhimself - Monday, December 19, 2005 - link
Youre right about the low latency L1/L2 caches on the Dothan, but the P4 (Williamette/Northwood) has those as well. But the P4 FPU is only powerful in SSE2 mode where it can load store larger chunks of data. Not all games use that unfortunately.saratoga - Monday, December 19, 2005 - link
You're wrong on several points.First:
Dothan L2 latency (clks): 10 clks
Northwood L2 latency (clks): 18 clks (approximately)
So Dothan's L2 cache is roughly 2x as fast and 4x as large. If you compare prescott with its amazingly slow L2, the situation is even more biased towards Dothan. Clearly, in terms of cache performance Dothan has a massive advantage, at least once you're out of the L1.
Second, you're confusing SSE2 and vector processing. While SSE2 can perform vector ops, it also handles plan scaler as well. In x86-64 SSE actually replaces the traditional x87 unit. The relative performance of the two is irrelevent however, the P4 was faster in both.
coldpower27 - Monday, December 19, 2005 - link
Dothan I agree with as having 10 Cycle Cache.
Northwood has 16 Cycle Cache.
Well you also got to keep in mind northwoods clock frequency plays a role in speeding up the cache, accces latencies for Dothan @ 2.0GHZ vs Northwood @ 3.2GHZ are basically equivalent. Though the 2.26GHZ Dothan has the fastest cache of all.
AlexWade - Monday, December 19, 2005 - link
Although, "Core Duo" is a stupid name. Why does Intel have to be so different? "Core Duo" is a little confusing. Is Duo a code name? What?However, despite the stupid name, we've really turned a corner in performance. Intel can make a good CPU when they realized speed isn't the future. Looks like I should start considering replacing my old Pentium-M IBM T40p with the awesome battery life.
AMD needs to respond in kind with a great new CPU. The future looks bright. Competition is once again is good for everyone.
LuxFestinus - Tuesday, December 20, 2005 - link
The ambiguously gay duo, with Ace and Gary.:) An old SNL skit.ksherman - Monday, December 19, 2005 - link
Personally, i dont like that AMD is just sitting back, seemingly waiting for Intel to catch up... They need to kick Intel while their down. these new Processors from intel look really nice and i am likely to buy one, but in a mactel laptop. I am happy for INtel that they are catching up, but AMD really NEEDS to step up and do soemthing new.Calin - Tuesday, December 20, 2005 - link
AMD's income is lower than Intel uses for R&D. You really can't expect from AMD to develop something faster than Intel can.For AMD, to have an processor they could improve a step at a time since the introduction of the Athlon64/Opteron was a need - Intel is able to mantain several teams for microprocessor development, but AMD only has money for one. And AMD will milk the market for as much as possible, selling processors that are easy to make for prices that market will accept. If AMD will start selling a higher processor grade, they would need to reduce the price for lower speed processors. This is why the 2800+ and 3000+ are discontinued - they would have to sell them too cheap.