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Microsoft Says Tipping Point Already Reached

According to a source inside Microsoft, over 25 percent of Vista installations in the US at the end of last year were 64-bit. There were several major drivers for the switch to 64-bit, most related to cheap DDR2 DRAM.

Jon DeVaan, Senior Vice-President of the Windows Core Operating System Division, agrees. "From our point of view we believe that we have accomplished the tipping point in terms of 64-bit adoption. Now, this happened to a large degree because memory prices are coming down, and another dynamic that we've seen in the United States is that the retail channel is looking to use RAM upgrades as a way to boost margin. So what that means is that 64-bit machine run rate is increasing rapidly, and that means our ability to support those 64-bit machines fully in the broad ecosystem is a really important thing."

Any PC with 4GB of RAM or more must use a 64-bit installation of Windows in order to address the full amount of RAM. Typically a 32-bit installation would recognize a maximum of 3-3.5GB of RAM.

Instead of purchasing a 32-bit version and then having to change to 64-bit later when they purchase more RAM, many are choosing 64-bit at the start. Over 75 percent of Windows sales are based on OEM installations of new computers.

The majority of Core i7 platforms are also using 64-bit operating systems, due to the triple channel memory setup using more RAM.

If you bought Windows Vista as a retail packaged product, Microsoft offers a free 64-bit upgrade DVD for the cost of shipping and handling. The upgrade will be a full clean installation over the 32-bit version. Windows Vista Ultimate already includes 32-bit and 64-bit versions on the DVD.

Many OEMs also provide a free or low cost option to switch to 64-bit Vista.

Windows 7 is expected to be the last to natively run at 32-bits. The next major Windows revision after it will be 64-bit native, running 32-bit applications through the use of a compatibility layer.

Windows Server 2008 R2, the server version of Windows 7, is already exclusively 64-bit.

With the switch to Windows 7, it would be easiest for PC OEMs to adopt 64-bit exclusively. That would reduce the number of SKUs (Stock Keeping Units) and drivers that would be needed by half, not an insignificant number when you consider that Windows 7 will ship in at least 4 editions. Multiply that by at least 34 localized language versions.

Additionally, the price premium of DDR3 will drop significantly as 50nm production kicks in. DDR3 is the memory of choice for AMD's CPUs using the AM3 socket, as well as Intel's Core i7 and Core i5 (Lynnfield). Due to lower power consumption, DDR3 adoption on laptops is progressing rapidly as well.

"Put more simply, usage of 64-bit Windows Vista is growing much more rapidly than 32-bit. Based on current trends, this growth will accelerate as the retail channel shifts to supplying a rapidly increasing assortment of 64-bit desktops and laptops," said Chris Flores, a Director on the Windows Client Communications Team.

Since 64-bit Vista and Windows 7 can run 32-bit applications, the last remaining hurdle is driver compatibility. Many new devices now have 64-bit device drivers available for Vista, and those should be mostly compatible with Windows 7.

An important tool is the Windows Vista Compatibility Center. Devann thinks that 64-bit support will drive sales: "They can go here and look at 64-bit compatibility, and with the trend that we just saw this is a good place for communicating with your customers about your support for 64-bit, so that they can prefer your product if they have one of these 64-bit systems".

Devann addressed the crowd at WinHEC with the following message, "I urge everyone here to make sure that you have the right 64-bit support, and in general 32-bit software runs fine on 64-bit Windows, but when it comes to drivers, that's where the work is. And with this audience, it's something that we're all acutely aware."



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RE: Slight error
By TheLiberalTruth on 1/22/2009 12:28:13 AM , Rating: 3
True, PAE may allow for 64GB, however, not on any desktop OS.

http://en.wikipedia.org/wiki/Physical_Address_Exte...

Read the table there. XP and Vista are able to address only 4GB.


RE: Slight error
By quiksilvr on 1/22/2009 12:35:47 AM , Rating: 2
And technically speaking the 32 bit OS can handle 3.5 GB of RAM. I know its not 4 but its close and performance wise its still noticeably better than having 2 GB of RAM.


RE: Slight error
By StevoLincolnite on 1/22/2009 4:40:40 AM , Rating: 5
Theoretically Windows can support the full 4GB, but your hardware is going to allocate some of the address space (not the physical RAM) to the PCI bus, the video adapter memory address space, and other resources. 32-bit OSs need to use part of the full 4GB address space to address these resources, subtracting from the maximum memory you have available to the OS and applications.


RE: Slight error
By 16nm on 1/22/2009 10:29:28 PM , Rating: 2
That's right, and when you move to 64-bit then the addresses for these devices can be moved above the address space for the RAM thereby freeing it. I've seen WinXP access 3.99 GB of ram on some systems.


RE: Slight error
By SlyNine on 1/23/2009 5:58:20 AM , Rating: 2
Yea but the OS only allocates 2gigs to programs, Unless you.

A. Set the system to use the 3/1 memory switch. That can cause system crashes

B. The program has to be high memory aware.

It uses the rest for the kernel, and also like the other guy said. PCI buss, adapter memory all has to take a chunk out of that address space.

Vista 32bit in my eyes slowed development on Vista 64. All systems that could only run Vista 32 were pretty much inadequate for Vista in the first place. Its Ram barrier was also its minimum amount for smooth operation. Vista 32bit was a waste of time and a mistake.

I wish they wouldn't even bother with Windows 7 32bit.


RE: Slight error
By TheLiberalTruth on 1/22/2009 12:43:25 AM , Rating: 5
Heh...let me reword "not on any desktop OS" to "not on any desktop OS with appreciable market share". I wouldn't want to leave out Linux and it's ~1% market share or the handful of folks using Mac Pros. ;)


RE: Slight error
By Calin on 1/22/2009 3:31:03 AM , Rating: 2
Not to mention the people using BSDs as a desktop OS (FreeBSD mainly) :)


RE: Slight error
By foolsgambit11 on 1/22/2009 5:00:25 PM , Rating: 2
All you have to do is reparse the quote to make the article accurate:

"Any PC with 4GB of RAM or more must use a 64-bit installation of Windows in order to address the full amount of RAM."

The question is, does 'must use a 64-bit installation of Windows' mean that the PC can only address all of the RAM if it is running a 64-bit installation of Windows, or does it mean that a PC with an installation of Windows will only address all of the RAM if it is 64-bit? The latter is a true statement. The former isn't, and you don't even have to get into exotic memory addressing. Any 64-bit OS will address more than 4 GB of RAM, not just 64-bit WIndows. So we must assume the intended meaning is the latter - that if you are using Windows, you must have a 64-bit install to use more than 4 GB of RAM.

Unfortunately, the immediate and obvious parsing of the quote suggests the first meaning. The latter is stretching the grammar of the English language uncomfortably. So that's unfortunate writing.


RE: Slight error
By dagamer34 on 1/22/2009 12:49:43 AM , Rating: 2
Doesn't having 1GB video cards start chipping away at the usable amount of RAM a computer has available? I thought that's one reason why Microsoft states the amount of installed RAM in a user's system instead of the amount of RAM available to the OS at the behest of crying OEMs not wanting to deal with supporting 64-bit versions of Windows Vista?


RE: Slight error
By dani31 on 1/22/09, Rating: -1
RE: Slight error
By finalfan on 1/22/2009 3:36:13 AM , Rating: 5
It's not about the memory but the memory space. The video memory has to be mapped to somewhere in the 4GB memory space that a 32bit processor can address. The more video memory you have, the more memory space are occupied by it. The result is the main memory at that space cannot be accessed to the CPU. For 64bit processor, the video memory can be mapped to a space far beyond the main memory address which makes all main memory accessible.

http://en.wikipedia.org/wiki/MMIO


RE: Slight error
By on 1/22/09, Rating: -1
RE: Slight error
By Motley on 2/3/2009 8:59:10 PM , Rating: 1
You shouldn't say "never", because my video card takes 1768MB (1.7GB) of address space.


RE: Slight error
By sabrewulf on 1/22/2009 1:23:42 AM , Rating: 2
Given the context of the article, I don't think it was really necessary for amanojaku to post such information. I suspect he was just showing off. If the article had been about 64-bit adoption on servers then it might've been more relevant.


RE: Slight error
By TomCorelis on 1/22/2009 2:21:16 AM , Rating: 3
Windows Server editions have been using PAE for a while, I thought?


RE: Slight error
By Bremen7000 on 1/22/2009 7:10:03 AM , Rating: 3
I believe the desktop Windows OSes are intentionally limited to not take advantage of PAE. Good riddance to 32-bit, anyway, bring on the global 64-bit support.


RE: Slight error
By anotherdude on 1/22/2009 8:50:33 AM , Rating: 5
Yes, no current DESKTOP OS, from MS, will use PAE to support more than 4 gig. Word is they tried it at some point with XP but some drivers were not mapping properly so they stopped it. As was pointed out it still works in some server versions and on some other OSes.

From Mark Russinovich:

"64-bit Windows client SKUs support different amounts of memory as a SKU-differentiating feature, with the low end being 512MB for Windows XP Starter to 128GB for Vista Ultimate. All 32-bit Windows client SKUs, however, including Windows Vista, Windows XP and Windows 2000 Professional, support a maximum of 4GB of physical memory. 4GB is the highest physical address accessible with the standard x86 memory management mode. Originally, there was no need to even consider support for more than 4GB on clients because that amount of memory was rare, even on servers.

However, by the time Windows XP SP2 was under development, client systems with more than 4GB were foreseeable, so the Windows team started broadly testing Windows XP on systems with more than 4GB of memory. Windows XP SP2 also enabled Physical Address Extensions (PAE) support by default on hardware that implements no-execute memory because its required for Data Execution Prevention (DEP), but that also enables support for more than 4GB of memory.

What they found was that many of the systems would crash, hang, or become unbootable because some device drivers, commonly those for video and audio devices that are found typically on clients but not servers, were not programmed to expect physical addresses larger than 4GB. As a result, the drivers truncated such addresses, resulting in memory corruptions and corruption side effects. Server systems commonly have more generic devices and with simpler and more stable drivers, and therefore hadn't generally surfaced these problems. The problematic client driver ecosystem lead to the decision for client SKUs to ignore physical memory that resides above 4GB, even though they can theoretically address it."

Great read on the subject here:
http://blogs.technet.com/markrussinovich/archive/2...

The limitation is in virtual memory address SPACE - a 32 bit OS can address 4 gig TOTAL (2 to the 32 power is 4 gig)but it must reserve some of that space for other devices with addressable memory on them such as video cards for example, hence the reason a video card with a lot of Vram will take quite a chunk off of your 4 gig.

The system is not using the unused portion of your system RAM for video, the system ram that cannot be addressed just sits there, unused due to lack of available addresses in the 32 bit range.


"Paying an extra $500 for a computer in this environment -- same piece of hardware -- paying $500 more to get a logo on it? I think that's a more challenging proposition for the average person than it used to be." -- Steve Ballmer

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