One of the big concerns with Windows Vista is that its high-powered Aero user interface will drag down overall system performance, causing Vista performance to trail that of XP on the same hardware. Also, Vista seems "heavier" from a functional standpoint: Surely all of that additional goodness will have an adverse effect on Vista's performance.

I'll leave it to better minds than my own to provide detailed benchmarks for Windows Vista. I've read that games, however, will typically run 10 to 15 percent slower on Vista than they do on Windows XP, and while that difference will likely be noticeable to hard core gamers, it's unlikely to affect normal users. And over time, of course, faster PCs--and Vista-specific hardware like DirectX 10-compliant video cards--should narrow, erase, and then eventually reverse that gap.

My own unscientific observation is that Windows Vista performs roughly as well on the same hardware as does Windows XP, with a few caveats. First, you shouldn't expect a PC with 512 MB of RAM to run Windows Vista effectively, unless of course your normal workload involves running a single application at a time. Second, you're going to get the best performance, believe it or not, with Windows Aero, and not with the lower-end Windows Vista Standard and Windows Vista Basic user interfaces, assuming you've got a compatible graphics processor (and again, you almost certainly do). That's because Windows Aero offloads a lot of the onscreen rendering and processing requirements from the CPU to the GPU, freeing your system's microprocessor for other tasks. Aero is also inherently more reliable than the software renderers.

From a performance perspective, multi-core processors appear to be a Macguffin of sorts. On both XP and Vista, multi-core processors like the Intel Core 2 Duo are certainly more efficient and speedy than their single core predecessors. But Vista and XP pretty much handle multi-core processors identically. It will take a future reengineered Windows version to truly take better advantage of the unique capabilities offered by that kind of hardware.

64-bit, too, is a performance non-event, unless of course you're talking about high-end science, engineering, video rendering, or other niche applications in which you've installed more than 4 GB of RAM. Again, this is unscientific, but on the two 2 GB systems I've tested, the 64-bit version of Windows Vista Ultimate didn't outperform its 32-bit relations at all. And of course, the various incompatibility issues introduced by Vista x64 make this version tremendously less interesting for most users, at least for the short term.

What does all this mean? In the broadest possible way, Windows Vista appears to actually match, or come close to matching, Windows XP on the same hardware, as long as the underlying hardware exceeds the minimum recommendations for actually running Vista. And that is quite definitely not too much to ask.

Performance features

Anyone who's taken a chance on first generation operating systems--think Windows NT 3.1 or the initial version of Mac OS X--understands the performance sacrifice one must take to live on the bleeding edge. Equally foolhardy is the person who believes in Microsoft's minimum hardware requirements. I still remember the poor people who tried to install and run the floppy version of Windows 95 on 386SX PCs with 4 MB of RAM. There's a cautionary tale there somewhere.

Well, with Windows Vista, the situation has improved dramatically. Thanks partially to chipmakers backing off from ever-higher clock speeds to focus instead on more practical chip designs and to a steady stream of internal software improvements in Windows Vista itself, Vista should surprise people, performance-wise. It's not a dog.

That said, there are a few features in Windows Vista aimed directly at performance. In this part of the review, we'll look at those technologies as well as a few other issues that affect overall system performance.

Windows ReadyDrive

Windows Vista natively supports a new generation of hybrid hard drives coming soon from Samsung and other companies via a feature named Windows ReadyDrive. I haven't been able to test this feature yet because these hard drives aren't yet available, but here's how it works: The hybrid hard drives combine a standard hard disk with large amounts (1 GB or more) of non-volatile flash memory. This memory acts a cache of sorts, providing a number of benefits. First, the system will boot up and resume from various sleep states much more quickly, allowing users to get back to work more quickly. Because the hard drive, with all its moving parts, spins up much less frequently, you'll experience better overall performance and better overall battery life. (For this latter reason, the first generation hybrid hard drives will likely target the notebook market and not the desktop PC market.) Hybrid hard drives should also be more reliable than their standard drive cousins, again, because the moving parts won't need to spin up so often.

Interestingly, previous generation operating systems won't be able to utilize these hybrid hard drives unless of course the drive makers include drivers in the box to enable that support. But Vista supports this technology out of the box, so there's nothing to add or configure. If you have such a drive, Windows ReadyDrive will just work. It's a win-win.

I will attempt to get a hybrid hard drive as soon as possible to test this feature. I'm told they'll become available sometime in early 2007.

Windows ReadyBoost

The first time someone from Microsoft described Windows ReadyBoost to me, I thought the guy was kidding, because it just seemed too good to be true. ReadyBoost uses spare space on USB-based storage devices like memory keys to increase the performance of your computer. It does this by caching information to the USB device, which is typically much faster than writing to the hard drive. Information cached to the device is encrypted so it can't be read on other systems.

There are a number of caveats. Your USB device must meet certain speed characteristics or Vista will not allow it to be used in this fashion. Space that is set aside on a USB device for ReadyBoost cannot be used for other purposes, unless you reformat the device or remove it from service with the PC. And you cannot use one USB device to speed up more than one PC.

ReadyBoost seems to have the most impact on systems with less than 1 GB of RAM, which makes sense, and it clearly will benefit notebooks more than desktops, since it's often difficult or impossible to increase the RAM in a portable machine. Microsoft recommends configuring ReadyBoost with one to three times the amount of RAM you have installed in your system. So if you have 512 MB of RAM, you should try to dedicate between 512 MB and 1.5 GB of space for ReadyBoost on a USB device.

When you insert a compatible USB device into a Windows Vista machine, you will see a "Speed up my system" option at the bottom of the Auto Play dialog that appears. When you select this option, Vista will display the ReadyBoost tab of the Properties dialog of the associated device, letting you configure a portion of the device's storage space. It will recommend the ideal amount, based on the capacity of the device and your system's RAM.

The big question, of course, is: Does it work? And here, again, I will have to waffle a bit: Despite testing ReadyBoost on a number of systems, I've been unable to quantify the effect it's had. I'm curious if anyone out there has any data on this topic. But it does seem like a fantastic and inexpensive way to speed up PCs, especially portable machines.

Windows Experience Index

When you first install Windows Vista, the otherwise speedy process is curiously slowed down to a standstill right after you navigate through the Out of Box Experience (OOBE) screens after that final reboot: Setup displays the message "Please wait while Windows checks your computer's performance" along with a number of promotional screens showing off various Windows Vista features (in a bid, no doubt, to prevent you from getting too bored during this process). During this time, Windows is literally measuring the performance of your system, and if it can complete all the benchmarks it wants to run, it will assign you separate scores for various components of your system as well as an overall score for your PC. Curiously, the overall score, which is the Windows Experience Index, is not an average of the other scores. It is, instead, based on the lowest component score.

But that's not the weirdest tidbit about this feature. No, that accolade belongs instead to the range of scores which your system (and its various measured components) can obtain. Being a logical personal, you might assume that Microsoft would rate these things on a scale from 1 to 10, or perhaps 1 to 5. That would make a lot of sense. But instead, the highest possible score is 5.9. That's right, the scale goes from 1 to 5.9. You just can't make this stuff up. (To be fair, however, the score is open-ended to support new hardware advances as they happen.)

The Windows Experience Index supplies individual scores for your processor, memory (RAM), graphics, gaming graphics, and primary hard disk. On my Lenovo ThinkPad T60 notebook, the scores break down as follows:

Processor: 4.7
Memory: 4.5
Graphics: 4.6
Gaming graphics: 4.0
Primary hard disk: 4.4

Because the lowest score--for Gaming graphics--is 4.0, the overall score, or Windows Experience Index, is 4.0 as well. I guess you're only as good as the weakest link in the chain. (These scores, incidentally, are pretty good for a notebook. The machine in question includes a dual-core Intel Core Duo T2500 processor running at 2 GHz, 1 GB of RAM, and an ATI Mobility Radeon X1400 with 128 MB of RAM.)

Right now, the Windows Experience Index isn't particularly valuable unless you've got a pretty high-end system and would like to brag about its score to your other geeky friends. But if this scoring system takes off as Microsoft hopes it will, various application and game makers will provide the lowest Windows Experience Index score required to use their software, making it easier for consumers to understand which software will and will not work on their system. To see a preview of this functionality, open up the Games Explorer, which supplies both required and recommended Windows Experience Index scores for each of the games that come with Windows Vista.

To view your Windows Experience Index score after Vista is installed, open the System Properties window (right-click Computer and choose Properties). Then, you can click the Windows Experience Index link to view the more detailed components rating list, and even re-run the benchmarks if you've recently installed new components.

Windows SuperFetch

Windows Vista uses a new version of SuperFetch that causes frequently-accessed applications to start up more quickly than is possible on Windows XP. SuperFetch works behind the scenes, examining how you use your PC over time. Then, it prioritizes the caching of applications in RAM based on your usage patterns. SuperFetch also ensures that your applications are given higher priority than background tasks, so the system is always responsive, even if you're stepped away for a while and have just returned.

SuperFetch answers the infamous "lunch" problem which afflicts Windows XP and previous Windows versions. In those systems, a user would walk away from the PC for lunch or some other duration, leaving the operating system to its own devices. Depending on the version of Windows we're talking about, the most-recently used applications would exit the system cache and the OS might begin working on various background tasks. But when the user returned from lunch and started using their applications again, the PC would be sluggish for a while, as if tired from the long time off. In Vista, this doesn't happen anymore. In fact, Vista is smart enough to understand that you may run certain applications at certain times of day. In such cases, it will pre-cache those applications, supplying even better performance.

It's not possible to configure Windows SuperFetch in any way, to my knowledge. It just sits in the background ensuring that your system is always running optimally.

Automatic Disk Defragmentation

On a related note, the updated version of Disk Defragmenter found in Windows Vista now works in a similar fashion. Rather than supply the familiar visual view of your fragmented hard drive and require you to manually defrag it on a regular basis, Disk Defragmenter now runs automatically (once a week by default) to ensure that your hard drive is regularly defragged. What a great idea. And best of all, you don't have to do anything for this to work: Disk Defragmenter is enabled by default. Bravo.

Sleep

While Windows has supported advanced power management features for quite some time, recent versions have suffered from two issues, one catastrophic: A surprisingly large percentage of Windows XP-based PCs were unable to successfully move into or out of the default Standby state, in which the screen dimmed, the hard drive spun down, and the system generally because unresponsive until it was woken up again. Additionally, the useful Hibernate state, in which the contents of RAM are written to the hard drive so that users can pick up later where they left off, with all their running applications and open documents intact, worked well but took a long time, especially on systems with lots of memory.

Enter Windows Vista, which largely replaces both Standby and Hibernate with a new power management mode called Sleep. (Technically speaking, Hibernate is still available, but it's been deprecated in Windows Vista.) Put simply, Sleep combines the best features of Standby with the best features of Hibernation, and it's far more reliable than Standby ever was. With the new Sleep state--which is the default power management mode on Vista notebooks--the system appears to turn off and turn back on in just 2-3 seconds. If you leave a portable system in a Sleep state for long enough on a portable system which is running on battery power, it will transition into Hibernate automatically before the battery dies.

The big innovation here is that it actually works for a change. Unlike the Standby feature in Windows XP, Vista's Sleep function is very reliable. And by default, the power button in the Vista Start Menu triggers Sleep, and not a dialog of power management choices like you'd get in Windows XP. You can, of course, configure this to your heart's content, though the UI for doing so is needlessly complex.

Power management and performance

While we're discussing the new Sleep state, I should also mention that Windows Vista supports three simple power management profiles, or power plans, and the default choice on notebook computers (and sometimes, curiously, on desktop systems) does not provide the best possible performance. To see how your system is configured for performance, mouse over the power management icon in the system tray: You'll see a notation in the bottom of the pop-up window that tells you which power plan you're using (the choices are Balanced, Power Saver, and Performance). To get the best possible performance--by sacrificing some battery life, of course---click the icon and choose Performance from the resulting pop-up. Or, click More Power Options to enter into Vista's maze of power management configuration choices.

Microprocessor and RAM support

As noted in Part 2 of this review, different versions of Windows Vista support different processor and RAM configurations. So it stands to reason that you will get the best performance if you choose the Vista versions that support the most physical processors and the largest amounts of RAM, and configure the system with the maximum possible for each.

All versions of Windows Vista except for Home Basic support dual processor PCs, yet another reason to skip out on Microsoft's new bargain basement Windows version. But all Vista versions, including Home Basic, support an unlimited number of processor cores. That means today that any Vista version will take full advantage of Intel's Core 2 Duo processor, and when Intel's four-core processors begin appearing soon, they'll be natively supported as well.

On the memory front, all 32-bit versions of Windows Vista support a maximum of 4 GB of RAM, which is dictated by address space limitations of 32-bit processors. But you can go well beyond 4 GB of RAM on 64-bit Vista versions, thus dramatically increasing the potential performance of your PC (assuming you can even take advantage of this capability). The x64 version of Windows Vista Home Basic is limited to 8 GB of RAM, while Vista Home Premium supports 16 GB. Other 64-bit Vista versions (Business, Enterprise, and Ultimate) support 128 GB of RAM or more. I'm sure you'll need that much RAM to run the next version of DOOM.

Final thoughts

On reasonably modern hardware, you'll find that Windows Vista runs just fine, thank you very much, and it's likely that most people won't notice any performance differences, when compared with XP, at all. On new PCs, of course, this won't be an issue, and Windows Vista will run like the proverbial greased pig. Much has been made of Vista's supposedly heady hardware requirements, but unless your current PC could serve as a prop on an episode of "The Flintstones," you shouldn't have anything to worry about.

Next: Windows Vista Features: Reliability Features.