Half of Windows 7 Machines Running 64-Bit Version

nk497 writes "Microsoft has said that nearly half of machines running Windows 7 are using the 64-bit version, up from just 11% of PCs running Vista. The 32-bit version is limited to 4GB RAM, while the 64-bit version allows 192GB, as well as added security and virtualization capabilities. While Microsoft is pushing 64-bit as a way to gain performance in the OS, it earlier this year advised users to install the 32-bit version of Office 2010, 'because currently many common add-ins for Office will not function in the 64-bit edition.'"

Comments

Why, oh why?

[palegray.net]

Is there a good technical reason for 32-bit Windows 7 not supporting more than 4 GB of RAM, period? PAE has been in use for a long time now, and while you can't have a single process that exceeds 3 GB in Linux (tunable, I'm given to understand, can also be a 2 GB per process limit in some installations), you can definitely go past 4 GB of total system memory. Windows Server 2008 Enterprise supports 64 GB per 32-bit system...

Re:Why, oh why?

[TheRaven64]

PAE adds another layer to the page tables (as does 64-bit addressing), which makes TLB misses more expensive, so you don't want to enable it on systems that don't have more than 4GB of RAM. Given that very few machines ship with more than 4GB of RAM, but a 32-bit processor, it's likely that this would be a configuration that would get very little or no testing (especially from driver developers) so would be potentially very buggy.

A lot of PCI devices are 32-bit, so drivers need to use bounce buffers to do DMA transfers to physical memory over the 4GB line. This is something that device drivers designed for 32-bit systems won't do, because they can just pass 32-bit physical addresses straight to the device on the systems they were written for.

Artificial limits R US (tm)

[Twinbee]

Is there a reason they can't go above the artificial limit of 192 GB?

64 bit CPUs should be able to access up to 18,446,000,000 GB of memory space, so I see no reason for the arbitrary limit.

Re:Artificial limits R US (tm)

[Anonymous Coward]

18446000000 / 16GB = 1,152,875,000. Note at 400MHz(the minimum DDR3 speed) light travels about 1 meter per clock cycle. Such a memory array would be much larger than 1 cubic meter, making DDR latency numbers impossible to meet even with lightspeed interconnects.

Yes, IAAAD(I am an ASIC designer)

Re:Statistics, statistics

[Sycraft-fu]

It truly amazes me how lazy developers are when it comes to supporting new things. They whine and bitch and drag their feet and blame MS, rather than just admitting they have to learn something new and doing it.

For example back in the Windows 2000 days I had a professional sound card. It had Windows NT drivers, but had some limits since NT wasn't good at sound. 98 was the preferred OS. Well when 2000 came out, the refused to release 2000 drivers. They claimed that the kernel mixer introduces 30ms of delay that you couldn't get around and that was unacceptable for pro work, etc, etc. Just use the NT drivers even though that caused some problems.

I (and probably many others) found the MSDN page on kernel streaming and sent it to them, showing them they were full of shit. Finally, many months later, they released a WDM driver... That supported only 2 of the interfaces 10 inputs and outputs. They claimed that WDM could only support one stereo set, that's it. A built in limitation by MS, nothing you can do about it. In frustration I e-mailed MS and I think they were sufficiently surprised by the stupidity of the statement that a developer actually responded and showed me where to find the docs. Turns out that WDM support lots of audio devices, either enumerated as multiple stereo pairs (as old style drivers did) or as a single multi-channel output. in fact you could do both at once.

So that went off to them and they ignored it for a long time and finally got out a real, full, WDM driver that was buggy as shit. The proceeded to work on the bugs and eventually had a nice driver. They decided they really liked WDM at that point, and quickly stopped supporting the older formats. It went from "We can't do it," to "This is the only way to do it.

But it took like a year and a half.

Many, perhaps most, developers are extremely, EXTREMELY lazy at updating to new technologies and fixing up their code. They want to keep doing shit the same way they always have, no matter how outdated that is.