May 3rd, 2009
How many Intel CPUs will fail the XP Mode test in Windows 7?
Some of the most popular PCs on the market today, equipped with fast and powerful dual- and quad-core CPUs, won’t be able to use the vaunted Windows XP Mode in Windows 7.
When Windows Vista launched, Intel and Microsoft both got a black eye over the infamous “Vista Capable” logo. That sticker was slapped on PCs running some of Intel’s most popular graphics chips, even though they wouldn’t run the new Aero graphics. Microsoft is still battling in court with angry customers (and their lawyers) who felt betrayed by that marketing campaign.
Now, three years later, it appears to be time for the “Vista Capable” sequel. How much positive Windows 7 buzz will be wiped out in coming weeks and months when consumers and business buyers discover that a heavily hyped new Windows 7 feature, XP Mode, won’t work on some Intel-based products? The problem is caused by the Byzantine way Intel packages its CPU technology—adding, removing, and tweaking features like bus speed and cache size to hit the widest variety of price points for PC makers.
The new Windows Virtual PC (now available as a beta release for the Windows 7 Release Candidate) requires hardware-assisted virtualization. For your PC to run XP Mode in Windows 7, the CPU has to support Intel Virtualization Technology (Intel VT) or AMD Virtualization (AMD-V), and this support has to be enabled in the BIOS.
In the case of Intel’s phenomenally confusing product matrix, VT support is added and removed from CPU models for reasons that have more to do with marketing than technology. You can’t necessarily tell from the model number whether VT support is present or not. If you buy a brand-new PC and pick the wrong CPU, Windows Virtual PC won’t be able to host the virtual machine that powers XP Mode. And spending more money can actually hurt you in some configurations.
Here’s a real-world example. Dell’s Vostro 420 is a well-built, no-frills desktop PC designed for the small and medium business market. The screen grab below shows the current lineup of CPUs that you can choose from when you build this system to order at Dell’s website. Four of the six options support Intel VT; I’ve circled the two CPUs that don’t support VT.
If you stay with the entry-level CPU, XP Mode won’t run on this PC. So you decide to upgrade the E7400 to an E8500 for $90. Problem solved! Although both are members of the Core 2 Duo family, the E8500 supports Intel VT, whereas the E7400 doesn’t.
But then you realize that for a measly $40 more you can go from a dual-core processor to the Core 2 Quad Q8200. Great idea! Unless you want to use any of those four CPU cores to run Windows Virtual PC, that is. The Q8200, you see, lacks VT support. For that, you need the Q9400, Q9550, or Q9650.
I had noticed this previously but revisited the topic today after my buddy Dwight Silverman commented, with some surprise, that his desktop PC with a Core 2 Quad Q8200 won’t support XP Mode (“Bummer”), but the Core 2 Duo E6600 in an older Mac does just fine. (“I guess I’ll be upgrading my Boot Camp partition”)
I haven’t looked at Intel’s CPU matrix since last summer, when I was researching which quad-core CPUs had some staying power. I have purchased three PCs with quad-core CPUs since then; thankfully, I avoided the Q8xxx series and went with the Q6600, Q9300, and Q9450, all of which support Intel VT.
This stuff is confusing, though. So, as a public service, I paid a visit to the Intel Processor Spec Finder, where I searched all modern CPU families, desktop and mobile, to see which ones support hardware virtualization. I copied the results to an Excel spreadsheet, created a few PivotTables, and came up with quick reference tables that can help you see at a glance whether your CPU can pass the XP Mode test.
Update: A reader passes along a recent news report that Intel plans to update five of its processors to add VT support: the Core 2 Quad Q8300, Core 2 Duo E7400 and E7500, and Pentium E5300 and E5400 are slated to get the new designs. That figures to make the landscape even more confusing, with some CPUs having VT support or not depending on the revision number.
If you’re curious whether your system has Intel VT support, check out the tables on the following two pages.
Next page: Intel desktop CPUs –>
Ed Bott is an award-winning technology writer with more than two decades' experience writing for mainstream media outlets and online publications. See his full profile and disclosure of his industry affiliations.
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| 05/03/09
