Linked by Thom Holwerda on Wed 28th Nov 2012 15:17 UTC
Windows "As we pass the one month anniversary of the general availability of Windows 8, we are pleased to announce that to-date Microsoft has sold 40 million Windows 8 licenses. Tami Reller shared this news with industry and financial analysts, investors and media today at the Credit Suisse 2012 Annual Technology Conference. Windows 8 is outpacing Windows 7 in terms of upgrades." Not bad, but there are the usual asterisks, as Ars notes.
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RE[4]: Comment by MOS6510
by MOS6510 on Wed 28th Nov 2012 20:34 UTC in reply to "RE[3]: Comment by MOS6510"
MOS6510
Member since:
2011-05-12

Why doesn't XP run well on multi core PCs and isn't there a fix?

We recently bought new PCs at work, Windows 7. Our old PCs, duo cores, ran XP and they were pretty awfull. But Linux flies on them and Windows 7 is also very decent.

Reply Parent Score: 2

RE[5]: Comment by MOS6510
by lucas_maximus on Wed 28th Nov 2012 20:40 in reply to "RE[4]: Comment by MOS6510"
lucas_maximus Member since:
2009-08-18

I think the kernel isn't designed for it. Vista's is slightly better, but isn't brilliant.

There is an actual blog post on how they designed the Windows 7 kernel to work well with Multi-core processor ... but I can't find it now.

Vista also used 300 MBs just for the Window Manager ... which IMHO was a bit shitty.

EDIT: I believe it was the idle time being adjusted that made the difference.

Edited 2012-11-28 20:47 UTC

Reply Parent Score: 2

RE[6]: Comment by MOS6510
by MOS6510 on Wed 28th Nov 2012 20:41 in reply to "RE[5]: Comment by MOS6510"
MOS6510 Member since:
2011-05-12
RE[5]: Comment by MOS6510
by WereCatf on Wed 28th Nov 2012 21:12 in reply to "RE[4]: Comment by MOS6510"
WereCatf Member since:
2006-02-15

Why doesn't XP run well on multi core PCs and isn't there a fix?


The kernel simply wasn't designed for multi-core systems as at the time such systems were first and foremost high-end devices and the situation was not anticipated to change. If you think back to those times people and companies were entirely focused on megahertz - race -- including Intel and AMD -- and people just assumed we'd be running into hundreds of gigahertz on a single core.

There are various kinds of fixes to make XP run slightly better on dual-core systems, but even these do not really fully fix the situation and XP's kernel still suffers a serious penalty on three cores or more.

Reply Parent Score: 3

RE[6]: Comment by MOS6510
by tylerdurden on Wed 28th Nov 2012 23:47 in reply to "RE[5]: Comment by MOS6510"
tylerdurden Member since:
2009-03-17

XP was definitively designed with multiprocessing in mind. The NT kernel already supported natively SMP, MMP, and (cc)NUMA years before XP for that matter.

The scheduler and some subsystems have been tweaked through the years, so the newer kernels do appear to behave "faster" for most interactive tasks. Computers keep also getting faster as well.

There were some artificial limitations in the number of cores supported between the "home" (only 1 socket supported) and "pro" versions of XP. But I have used a 16 core workstation using XP, and it ran SMP workloads like a champ.

Edited 2012-11-28 23:50 UTC

Reply Parent Score: 3

RE[5]: Comment by MOS6510
by zlynx on Wed 28th Nov 2012 21:24 in reply to "RE[4]: Comment by MOS6510"
zlynx Member since:
2005-07-20

There were several "fixes". For example, there's a dual-core optimizer program that AMD wrote and gave to gaming companies to fix XP for their Athlon64 X2 CPUs.

I'm not quite sure what it does, actually, but it seems to help.

There were quite a lot of video drivers that updated to optimize dual-core and hyperthread support for XP. I believe they forced various driver threads onto specific cores so the XP thread scheduler wouldn't get involved.

Some of those tweaks are less optimal now that CPUs have four/eight cores/threads and the Windows 7 and 8 thread schedulers.

Reply Parent Score: 2