It still seems like dual core processors have arrived rather suddenly. Just a few short months ago, we were blissfully unaware, running our single benchmarks and counting gigahertz. As it turns out, HyperThreading was just a small glimpse of what was to come. These new dual core processors present an entirely new paradigm in terms of measuring performance and value, and so we've had to spend considerable time determining the best way to approach these latest fruits of the industry. Like it or not, dual core is here, and we’re no longer playing the same ballgame.
This first Intel dual core processor is essentially two Prescott dies grafted together. Each core has its own, separate 1 MB L2 cache, while the two cores share an interface to the front side bus. Intel will offer two product lines, the Pentium Extreme Edition and the Pentium D. The former has HyperThreading capability, giving it four logical cores, while the latter does not. The Extreme Edition is available initially at 3.2 GHz only, while the Pentium D will be available in speed grades from 2.8 GHz to 3.2 GHz initially.
Unfortunately, neither of Intel's new dual core brands are backwards compatible, and require a new chipset. That new chipset is the 955X, which, aside from dual core support, is otherwise very similar to the 925X chipset. A lower cost 945X chipset will follow shortly. Score a point for AMD here, whose dual core processors will be backwards compatible with existing boards.
The Intel 955X motherboard used to evaluate the Pentium 4 Extreme Edition 840
To begin to evaluate our Pentium Extreme Edition, we devised a couple of simple yet telling multitasking scenarios. We’ve skipped single application benchmarking, as the processor will simply perform identically to a 3.2 GHz Pentium 4. We compared the performance of the Extreme Edition to a Pentium 4 660 that we've been using in our labs for some time.
In the first scenario, we opened what we considered to be a normal suite of background applications, including MSN Messenger, Windows Media Player playing a playlist, and a couple browser windows. We proceeded to open Adobe Photoshop and edit a large 12 MB scanned photo, to which we applied a 3D transform filter. In the foreground, three large PDF files were opened, and scrolled through as the Photoshop filter was processing. We measured the time to complete the Photoshop filter while scrolling through these large PDFs.
Using Photoshop filter while multitasking
Pentium 4 660 w/o HyperThreading: 76 secs
Pentium 4 660 w/ HyperThreading: 69 secs
Pentium Extreme Edition 840: 52 secs
Not only did the PDF display much more smoothly, but the Photoshop filter in the background, not having to share processing resources with the foreground application, completed 25% faster. In the next scenario, we opened the same host of background applications. We brought a browser window to the foreground, and loaded a complex Shockwave Flash animation, while in the background, we measured the time it took WinRAR to archive a 70 MB file.
Archiving a 70MB file while multitasking
Pentium 4 660 w/o HyperThreading: 140 secs
Pentium 4 660 w/ HyperThreading: 74 secs
Pentium Extreme Edition 840: 72 secs
The results here are extremely interesting. The single core Pentium 4 660 obviously has the execution resources to handle both tasks simultaneously, but without HyperThreading, the dispatch resources just aren’t sufficient given the complex Flash animation. The dual core processor does show a small improvement, but HyperThreading was already doing a pretty good job on its own. In our last scenario, we opened the normal suite of background applications, plus a few additional browser windows. We started copying a large DVD file on the hard disk, and then measured the time it took to open Outlook Express.
Copying a DVD file while multitasking
Pentium 4 660 w/o HyperThreading: ~15 secs
Pentium 4 660 w/ HyperThreading: ~14 secs
Pentium Extreme Edition 840: ~2 secs
Users of dual processor systems often insist that they're much more responsive than single core systems, and this test demonstrated that very well. In a more subjective analysis, we found the dual core system to be much more responsive. Even with multiple complex applications running, the dual core system would proceed smoothly where the single core systems began to stall.
The Intel 955X chipset is hiding behind a rather large passive heatsink
So which is better? That's just the problem, neither is universally better. We're talking about apples and oranges here. For a user that needs the best possible single application performance, and multitasking is not a priority, a faster single core processor is still the best bet. As our second scenario showed, even simple multitasking is sometimes better handled by a single, faster HyperThreaded processor. For heavy multitasking use, though, there’s simply no beating these dual core processors.
I have, at the time of writing this, thirteen windows and six tray applications running, and the dual core system provides for a much smoother and more pleasant experience. No one can deny that the potential of dual core systems is enormous. But for consumers today, we leave you with the same advice we've left time and time again; know your uses, know your budget and tastes, and then choose whether the apple or the orange is best for you.