Comparing Windows 95, Windows NT 3.51, and Windows NT 4.0

How memory affects system performance

If you're going to roll out or upgrade your office's (or enterprise's)Windows client systems, you probably want to know whether Windows NT or Windows95 is faster. Knowing which OS is faster and under what circumstances candetermine which one you deploy. The difference in cost is also a factor.

Design Factors
Win95 was designed as a replacement for Windows 3.x, so it runs most old DOSand 16-bit Windows applications and drivers. Win95 also runs all the new 32-bitapplications, even some that were originally designed for NT. Win95 hassophisticated features such as pre-emptive multitasking and built-in multimediasupport. It can run in as little as 4MB of memory on a 386-compatible processor.

NT was designed from the ground up to run business applications. Itsfeatures include true 32-bit application support, true pre-emptive multitaskingand multithreading capabilities, security, fault tolerance, reliability, asecure file system (NTFS), and support for RISC-based and multiprocessorsystems.

NT requires greater system resources, such as a 486-compatible processor,16MB of memory, and 120MB of hard-disk real estate; has nobackward-compatibility with DOS and Windows 3.x 16-bit device drivers; andoffers limited support for older DOS and Windows 3.x applications, although itwill run the majority of them.

The Test
I tested Win95, NT Workstation 3.51, and NT Workstation 4.0 on a Pentium Prosystem, an HP 200MHz Vectra XA with 256KB cache. (The system came preloaded withExtended Data Output--EDO--RAM, which I tested for speed as you can see in "EDORAM," below.) I used our Windows NT Magazine Lab benchmark package,which we designed to execute a script over Adobe Photoshop and Elastic Reality.I ran this benchmark on the Vectra XA system with 16MB of memory and wassurprised to find that Win95 was quicker than NT 3.51 and 4.0 by about 30percent.

About this time, I received the BABCo SYSmark32 benchmark, which measuresthe time that real-world applications take to run predefined scripts. It is muchlike our benchmark but uses Adobe PageMaker, CorelDRAW 6.0, Lotus Freelance 96,Lotus WordPro 96, Microsoft Excel 7.0, Microsoft PowerPoint 7.0, Microsoft Word7.0, and Paradox 7.0 as its test applications.

Graph 1 shows that Win95 is about 18 percent faster than NT 3.51 and,interestingly, 20 percent faster than NT 4.0 with the same system configuration.However, when I looked at the results for specific applications, I noticed thaton NT 4.0, the Adobe PageMaker, CorelDRAW 6.0, and Microsoft Word 7.0 scriptsran as fast as or faster than on Win95, and the Adobe PageMaker and Paradox 7.0scripts ran faster on NT 3.51 than either Win95 or NT 4.0.

Wondering about the difference in performance, I added 16MB of memory tothe Vectra XA, for a total of 32MB, and ran the tests with Win95. I had heardthat performance on Win95 was supposed to stay the same or decrease with morethan 16MB of memory. So, I was surprised when it ran the scripts about 15percent faster, as Graph 2 shows.

I executed the same test with NT 4.0 and was amazed to see that it ran morethan 50 percent faster than before. This result was a 28 percent improvementover Win95 at this configuration. I ran the same test with NT 3.51, and theresults were not as impressive, although I did see a gain of more than 16percent.

With such a performance gain, I wondered whether doubling the memory to64MB would double the performance again. I put 64MB of memory into the systemand ran the tests again. The results in Graph 3 show no significant performanceimprovement, although NT 4.0 was the clear leader with a gain of 7 percent fromthe previous test. NT 3.51 was 14 percent faster, and Win95 gained only 4.5percent.

Overall Comparisons
Seeing results that you can easily use to improve a slow system'sperformance is nice. The real world is not so nice and neat: You probably runmultiple applications, device drivers, OS services, and System Tray applicationsat the same time. The BAPCo SYSmark32 benchmarking software runs a script over asingle application, timing how long executing and then rebooting the systemtakes after each run. This approach is useful to test how well a specificapplication will run on a given system, but may not be a realistic test of thesystem.

Both NT and Win95 outperform each other, depending on how much memory youinstall, as Graph 4 shows. If you have fewer than 32MB of memory and run NT 4.0or are considering an upgrade, I recommend installing at least 32MB of memory.If you run Win95 and have more than 32MB of memory, NT 4.0 can give your systema turbo charge.