Subject: Reducing Color Depth can Impede Performance
Date: 2005-08-02 14:03:55
From: ChrisTyler
--------------------------------------------------------------------------
Reducing the color depth from 32 bits (24 bits padded to 32) down to
16 bits can save memory, which in turn can significantly improve performance
when you're using a system which shares memory between the graphics system
and the CPU (e.g., Intel i810 family).
However, if you're not short on RAM, using 16-bit graphics can
dramatically slow down graphics operations -- especially when the CPU is
doing the work -- depending on what operations you are performing.
At 32 bits per pixel, the CPU can write a full 32-bit word to change
the color of one pixel. When using 16 bits per pixel, there are two pixels
in every 32-bit word. To change the color of one pixel, the CPU has to read
the word from memory, perform an AND to preserve the unaffected pixel's
value, perform an OR to insert the affected pixel's value, and then write
the word pack to memory -- 4 operations instead of 1 (and that's when you're
changing the low-order pixel; add a 16-bit left shift when you're changing
the high-order pixel).
==================================================
Bagaimana pendapat Anda para Win XP experts? Trims sebelumnya.
Salam,
Agoes
[Non-text portions of this message have been removed]
--
www.itcenter.or.id - Komunitas Teknologi Informasi Indonesia
Info, Gabung, Keluar, Mode Kirim : [EMAIL PROTECTED]
:: Hapus bagian yang tidak perlu (footer, dst) saat reply! ::
## Jobs: itcenter.or.id/jobs ## Bursa: itcenter.or.id/bursa ##
$$ Iklan/promosi : www.itcenter.or.id/sponsorship $$
[@@] Jaket ITCENTER tersedia di http://shop.itcenter.or.id
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ITCENTER/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
