test system specs:
computer hardware:
processor:	amd athlonxp 1900+
clock speed:	1.66 ghz 12.5 x 133 10 x 166
motherboard:	msi kt3 ultra-aru epox 8kha+
chipset:	via kt333 (msi) via kt266a (epox)
videocard:	MSI GeForce 3 Ti500 (MS-8850)
Sound Card:	N/A
Network Card:	DLink DE-528CT
Memory:	256MB Corsair PC2400 CAS2 DDR
Hard Drive:	Samsung SV6004H 5400RPM UDMA100 60GB
CDROM:	Panasonic 48x CD-ROM CR-594-B
Floppy:	Panasonic 1.44MB Floppy Drive
Heatsink:	AVC Sunflower
PowerSupply:	Enermax 431Watt
Software Setup	Windows 2000 Pro + SP2 VIA 4in1 4.37V DetonatorXP 22.80 DirectX 8.1
Benchmarks	SysMark 2001 Business Winstone 2001 Content Creation 2001 Winbench 99 SiSoft Sandra 2002 Pro 3DMark2001 SE Serious Sam 2 Return to Castle Wolfenstein

BAPCO Sysmark 2001	Source:MadOnion / BAPco

SYSmark2001 uses real world applications concurrently as an accurate way to test the system by following patterns that reflect the way real users work. SYSmark2001's workloads accurately represent today's updated business usage model. The benchmark runs at a realistic execution speed, with think times between application interactions, in order to emulate a desktop user's interaction with the operating system and applications.

Higher numbers denote better performance.

BapCo SysMark 2001 Benchmark Results
	Internet Content (FSB/Memory)	Sysmarks	Ranking
1.	8KHA+ 133/266 MHz	201
2	8KHA+ 166/333 MHz	210
3.	KT3 Ultra 133/266 MHz	198
4.	KT3 Ultra 133/333 MHz	205
5.	KT3 Ultra 166/333 MHz	213
	Office Productivity (FSB/Memory)
1	8KHA+ 133/266 MHz	163
2.	8KHA+ 166/333 MHz	175
3.	KT3 Ultra 133/266 MHz	165
4.	KT3 Ultra 133/333 MHz	169
5.	KT3 Ultra 166/333 MHz	184

Looking at the numbers, the MSI KT3 Ultra does get a tiny performance boost when the memory is clocked at 166 MHz with the FSB still at 133. Note that once the Epox 8KHA+ and MSI KT3 Ultra are at the same frequency, the scores are almost identical.

Winstone 2001	Source: Zdnet

Content Creation Winstone 2001 keeps multiple applications open at once and switches among those applications. Content Creation Winstone 2001's activities focus on what we call "hot spots," periods of activity that make your PC really work--the times where you're likely to see an hourglass or a progress bar.

Business Winstone is a system-level, application-based benchmark that measures a PC's overall performance when running today's Windows-based 32-bit applications on Windows 98 ME, Windows NT 4.0 (SP6 or later), Windows 2000, Windows Me, or Windows XP which runs real applications through a series of scripted activities and uses the time a PC takes to complete those activities to produce its performance scores.

Winstone 2001 Benchmark Results
	Content Creation (FSB/Memory)	Scores	Ranking
1.	8KHA+ 133/266 MHz	74.5
2	8KHA+ 166/333 MHz	77.3
3.	KT3 Ultra 133/266 MHz	75.3
4.	KT3 Ultra 133/333 MHz	76.0
5.	KT3 Ultra 166/333 MHz	77.5
	Business Winstone (FSB/Memory)
1	8KHA+ 133/266 MHz	46.2
2.	8KHA+ 166/333 MHz	49.9
3.	KT3 Ultra 133/266 MHz	46.2
4.	KT3 Ultra 133/333 MHz	47.1
5.	KT3 Ultra 166/333 MHz	50.1

As we can see here, Content Creation 2001 and Business Winstone 2001 verify what SysMark2001 says. The KT333 does give a very slight performance boost in office based applications when the memory is set to run at 333 MHz. When the two boards are clocked at the same speed, they perform identical to each other.

Winbench 99 V1.2	Source: e-Testinglabs.com

WinBench 99 is a subsystem-level benchmark that measures the performance of a PC's graphics, disk, and video subsystems in a Windows environment. WinBench 99's tests can run on Windows 95, Windows 98, Windows NT, Windows 2000, and Windows Me systems.

WinBench 99 v1.2 Benchmark Results
	MSI KT3 Ultra-ARU	Score	Ranking
1.	Business Disk - 133/266 MHz	5750
1a.	Business Disk - 133/333 MHz	6010
1b.	Business Disk - 166/333 MHz	5850
2.	High-End Disk - 133/266 MHz	15800
2a.	High-End Disk - 133/333 MHz	16000
2b.	High-End Disk - 166/333 MHz	14300
3.	Business Graphics - 133/266 MHz	835
3a.	Business Graphics - 133/333 MHz	841
3b.	Business Graphics - 166/333 MHz	876
4.	High-End Graphics - 133/266 MHz	1590
4a.	High-End Graphics - 133/333 MHz	1600
4b.	High-End Graphics - 166/333 MHz	1660

With the memory at 333 MHz, the HDD portion of this benchmark does get a very little performance increase, however as we see when overclocked, the scores are lower. This is likely due to the fact that HDD's don't work as well with higher PCI timings.

For AGP/graphics performance, the more bandwidth the better. When the FSB is in sync with the memory, the AGP seems to love running higher then usual.

Sisoft Sandra 2001	Source: Sandra

Sandra is designed to test the theoretical power of a complete system and individual components. The numbers taken though are again, purely theoretical and may not represent real world performance.

SiSoft Sandra 2001 Benchmark Results
	MSI KT3 Ultra-ARU	Score
	Multimedia Benchmark (FSB/Memory)
1.	Integer SSE - 133/266 MHz	9055 it/s
1a.	Integer SSE - 133/333 MHz	9055 it/s
1b.	Integer SSE - 166/333 MHz	9055 it/s
2.	Floating-Point SSE - 133/266 MHz	10657 it/s
2a.	Floating-Point SSE - 133/333 MHz	10657 it/s
2b.	Floating-Point SSE - 166/333 MHz	10663 it/s
	CPU Benchmark (FSB/Memory)
3.	Dhrystone ALU - 133/266 MHz	4578 MIPS
3a.	Dhrystone ALU - 133/333 MHz	4608 MIPS
3b.	Dhrystone ALU - 166/333 MHz	4601 MIPs
4.	Whetstone FPU - 133/266 MHz	2309 MFLOPS
4a.	Whetstone FPU - 133/333 MHz	2309 MFLOPS
4b.	Whetstone FPU - 166/333 MHz	2311 MFLOPS
	Memory Benchmark (FSB/Memory)
5.	Integer ALU - 133/266 MHz	2066 MB/s
5a.	Integer ALU - 133/333 MHz	2087 MB/s
5b.	Integer ALU - 166/333 MHz	2530 MB/s
6.	Float FPU - 133/266	1977 MB/s
6a.	Float FPU - 133/333 MHz	2004 MB/s
6b.	Float FPU - 166/333 MHz	2379 MB/s

Since the CPU speed is the same 1.66 GHz, the almost identical scores in the Multimedia and CPU benchmarks isn't surprising. As for the memory bandwidth it seems that the CPU/FSB cannot take advantage of the bandwidth available. At 333 MHz, the numbers are very close to that of the 266 MHz. With the FSB running at 166, the bandwidth increases quite a bit!