Intel G41 graphics are slow while memory runs in dual channel mode.

[Gary Jennejohn]

On Fri, 17 Dec 2010 17:15:34 +0300
N V <VaNs9 at yandex.ru> wrote:

> Hello.
> 
> I have Compaq 500B with "Pentium(R) Dual-Core  CPU      E5300  @ 2.60GHz (2600.02-MHz 686-class CPU)."
> Video card is:
> %pciconf -lv | grep -i g41
>     device     = 'Intel G41 express graphics (PCIVEN_8086&DEV_2E32&SUBSYS_31031565&REV_033&115)'
> %grep -i intel /var/log/Xorg.0.log | head
> (--) PCI:*(0:0:2:0) 8086:2e32:103c:2a8c Intel Corporation 4 Series Chipset Integrated Graphics Controller rev 3, Mem @ 0xfe400000/4194304, 0xd0000000/268435456, I/O @ 0x0000dc00/8, BIOS @ 0x????????/65536
> (II) LoadModule: "intel"
> (II) Loading /usr/local/lib/xorg/modules/drivers/intel_drv.so
> (II) Module intel: vendor="X.Org Foundation"
> (II) intel: Driver for Intel Integrated Graphics Chipsets: i810,
>         Mobile Intel® GM45 Express Chipset,
>         Intel Integrated Graphics Device, G45/G43, Q45/Q43, G41
> (==) intel(0): Depth 24, (--) framebuffer bpp 32
> (==) intel(0): RGB weight 888
> 
> The system is:
> %uname -mor
> FreeBSD 8.2-PRERELEASE i386
> 
> There were 2GBs of memory running in single channel (one slot occupied). Everything was ok.
> I've added 2 more GBs (occuping the second slot). Now memory runs in dual channel. I have 4GBs. The system is i386, non-PAE, so ~3GBs are visible.
> I have latest KDE that is built from ports.
> And the problem: after adding memory, graphics (compositing, I think) became so slow rendering the effects, that after a second or less of some "desktop effect" KDE turns off desktop effects. XvMC is enabled in xorg.conf, if it matters.
> 

I doubt this has anything to do with dual-channel memory.  More likely
is that you're trying to use 4GiB with i386, which can cause all kinds
of problems.

You have two options, as fas as I can tell
1) run amd64, which can use the full 4GiB of memory
2) set hm.physmem to 3G (or maybe a little more) in /boot/loader.conf

-- 
Gary Jennejohn