News March 2, 01:13 Eastern Time
Mar. 01, 1999 (Computer Reseller News - CMP via COMTEX) -- New York -- All resellers would like to ask Intel Corp.: "Will a Pentium III processor deliver more performance than a Pentium II?" The CRN Test Center found the answer is yes, but the boost realized depends on the applications, operating system and hardware drivers in question.
All three must come together to achieve maximum results from the processor's 70 new single instruction-multiple data (SIMD) operating codes and other features. Already, support from application and IT-management ISVs is strong enough by itself to make Pentium III a worthwhile proposition for resellers. More than 50 software packages are scheduled for delivery within 90 days of the processor's release.
Operating system support from Microsoft Corp. on Windows 98 is excellent, less extensive in Windows NT 4.0 and nonexistent in Window 95. But the Test Center found performance gains under Windows 95 mainly because the benchmark software includes its own Pentium III support. Hardware support in the form of Pentium III-ready drivers is, for now, the domain of video-card manufacturers. (For more detail on software support for the Pentium III processor, see the online version of this story at www.crn.com)
Technology
The Pentium III processor has three advantages over the Pentium II. The architecture includes more floating-point registers and instructions; it can operate at higher frequencies; and it has improved cache-memory performance. The current Pentium III offerings include 450MHz and 500MHz processors, with faster versions to come before year's end. The processor speed advantage is accessible even to legacy software.
The new software-dependent SIMD instruction set allows the Pentium III to use fewer clock cycles to perform some operations. The processor can perform operations on entire sets of data instead of repeating the same operation on each chunk of data one at a time.
The processor no longer shares its floating-point registers with MMX technology. MMX calculations are performed while the processor runs its own floating-point calculations. The instructions and registers boost multimedia and speech-recognition performance. Pentium III-savvy software is required to reap those benefits. The Pentium III enhances cache hits without the need for special software. The processor predicts what data will be needed and stores it in advance.
Performance Analysis
When MultimediaMark 99 was run in Windows 95, the 350MHz Pentium II lagged behind the 450MHz Pentium II by 20 percent. So a 100MHz increase in processor speed is equivalent to a 20 percent boost for MPEG processing in Multimedia-Mark. The 450MHz Pentium III performed 10 percent better than its Pentium II counterpart. Windows 95 does not support the new instruction set, so the performance gains were due to the benchmark's own SIMD support. The performance gain is equivalent to a 50MHz increase in processor speed. The 500MHz Pentium III provided another 10 percent performance gain.
The boosts in the MPEG-1 scores remained nearly identical under Windows 98 because applications with their own SIMD support are not hampered or enhanced by the Pentium III-ready operating system. The inclusion of the image processing and audio-effects tests widened the gap between the 450MHz Pentium II and Pentium III processors, although the margin between the processors within each family remained nearly unchanged. That indicates the image processing and audio-effects tests contain more SIMD instructions than the MPEG tests.
Under Dragon Systems Naturally Speaking Professional 3.52 for Applications Launcher in Windows 95, the margin between the 450MHz processors rose slightly beyond 12 percent, but the margins between processors in each family tightened. The narrowing indicates the real-world application did not execute as much SIMD code as the synthetic benchmark. The Pentium III 450MHz processor held its advantage over its Pentium II counterpart, indicating its performance enhances speech recognition as much as it does the MultimediaMark 99 MPEG tests.
The Dragon Systems test under Windows 98 maintained almost the same margins between processors, which is to be expected since the application does not rely on the operating system for SIMD support. The inclusion of Microsoft Netshow Encoder 3.0 and Adobe Photoshop 5.0 tests widened the margin between the families to almost 15 percent, indicating those applications likely would experience greater performance increases than Naturally Speaking.
The same ratios were approximated by the Applications Launcher test under Windows NT, although the 500MHz processor did lose a little ground. The stability in the margins indicates that the DLL patch applied to Windows NT 4.0 is effectively equivalent to the Pentium III support in Windows 98 with DirectX 6.1 added for the test-suite applications.
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Pentium III plumbing:
- Includes better cache use.
- Provides new instructions and registers for multimedia.
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METHODOLOGY
Performance tests were done on 350MHz and 450MHz Pentium IIs and 450MHz and 500MHz Pentium IIIs with 512 Kbytes of cache using Futuremark's Multimedia Mark 99 and Intel's Business Applications Launcher V1.1. MultimediaMark 99 is a Pentium III-ready synthetic benchmark that generates empirical performance scores for MPEG-1 encoding, MPEG-1 playback, image processing and audio-effects generation.
The Business Applications Launcher generates empirical performance scores by timing how long a system takes to process scripted workloads in Pentium III-ready versions of Dragon Systems Naturally Speaking Professional 3.52. It also executes scripts for Adobe Photoshop 5.0 and Microsoft Netshow Encoder 3.0, which are dependent on the operating system for Pentium III capability.
Tests were performed under Windows NT 4.0, Windows 95 and Windows 98. Testing under Windows NT required the installation of Service Pack 4 and a Katmai.dll for Pentium III support. Windows 95 and 98 required DirectX 6.1 to fully support Intel's streaming SIMD extensions.
Not all combinations of tests, operating system and processor type are supported by the software used, so only data that shows comparative results between Pentium II and Pentium III processors are presented.
The test bed hardware consisted of two identical computers assembled on Test-Bed Pro test-and-assembly shelves to ease processor swapping. Each bench was powered by a Superpower SH-250ATX 250-watt, ATX-2.1 compatible, UL-listed power supply.
Each computer was composed of an Intel SE-440BX-2 motherboard; a Kingston 128-Mbyte, 100MHz DIMM; a 16-Mbyte Diamond Multimedia Viper 550 AGP video card with Pentium III-ready Nvidia drivers; and an Adaptec 2940U2W Ultra2 SCSI controller card. The drives included a Seagate Cheetah 18LP hard drive; a Philips CD-RW 400 rewriteable CD-ROM drive; and a Mitsumi 3.5-inch floppy drive.
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